Health Library

The Health Library is a collection of health and wellness resources created for learning and accessibility. Select a topic below for related health information or search for a topic in the search bar for more information on other medical conditions.

Spanish Translation

Oral Complications of Cancer Therapies (PDQ®): Supportive care - Patient Information [NCI]

This information is produced and provided by the National Cancer Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National Cancer Institute via the Internet web site at or call 1-800-4-CANCER.

General Information About Oral Complications

Oral complications are common in cancer patients, especially those with head and neck cancer.

Complications are new medical problems that occur during or after a disease, procedure, or treatment and that make recovery harder. The complications may be side effects of the disease or treatment, or they may have other causes. Oral complications affect the mouth.

Cancer patients have a high risk of oral complications for a number of reasons:

  • Chemotherapy and radiation therapy slow or stop the growth of new cells.

    These cancer treatments slow or stop the growth of fast growing cells, such as cancer cells. Normal cells in the lining of the mouth also grow quickly, so anticancer treatment can stop them from growing, too. This slows down the ability of oral tissue to repair itself by making new cells.

  • Radiation therapy may directly damage and break down oral tissue, salivary glands, and bone.
  • Chemotherapy and radiation therapy upset the healthy balance of bacteria in the mouth.

    There are many different kinds of bacteria in the mouth. Some are helpful and some are harmful. Chemotherapy and radiation therapy may cause changes in the lining of the mouth and the salivary glands, which make saliva. This can upset the healthy balance of bacteria. These changes may lead to mouth sores, infections, and tooth decay.

This summary is about oral complications caused by chemotherapy and radiation therapy.

Preventing and controlling oral complications can help you continue cancer treatment and have a better quality of life.

Sometimes treatment doses need to be decreased or treatment stopped because of oral complications. Preventive care before cancer treatment begins and treating problems as soon as they appear may make oral complications less severe. When there are fewer complications, cancer treatment may work better and you may have a better quality of life.

Patients receiving treatments that affect the head and neck should have their care planned by a team of doctors and specialists.

To manage oral complications, the oncologist will work closely with your dentist and may refer you to other health professionals with special training. These may include the following specialists:

  • Oncology nurse.
  • Dental specialists.
  • Dietitian.
  • Speech therapist.
  • Social worker.

The goals of oral and dental care are different before, during, and after cancer treatment:

  • Before cancer treatment, the goal is to prepare for cancer treatment by treating existing oral problems.
  • During cancer treatment, the goals are to prevent oral complications and manage problems that occur.
  • After cancer treatment, the goals are to keep teeth and gums healthy and manage any long-term side effects of cancer and its treatment.

The most common oral complications from cancer treatment include the following:

  • Oral mucositis (inflamed mucous membranes in the mouth).
  • Infection.
  • Salivary gland problems.
  • Change in taste.
  • Pain.

These complications can lead to other problems such as dehydration and malnutrition.

Oral Complications and Their Causes

Cancer treatment can cause mouth and throat problems.

Complications of chemotherapy

Oral complications caused by chemotherapy include the following:

  • Inflammation and ulcers of the mucous membranes in the stomach or intestines.
  • Easy bleeding in the mouth.
  • Nerve damage.

Complications of radiation therapy

Oral complications caused by radiation therapy to the head and neck include the following:

  • Fibrosis (growth of fibrous tissue) in the mucous membrane in the mouth.
  • Tooth decay and gum disease.
  • Breakdown of tissue in the area that receives radiation.
  • Breakdown of bone in the area that receives radiation.
  • Fibrosis of muscle in the area that receives radiation.

Complications caused by either chemotherapy or radiation therapy

The most common oral complications may be caused by either chemotherapy or radiation therapy. These include the following:

  • Inflamed mucous membranes in the mouth.
  • Infections in the mouth or that travel through the bloodstream. These can reach and affect cells all over the body.
  • Taste changes.
  • Dry mouth.
  • Pain.
  • Changes in dental growth and development in children.
  • Malnutrition (not getting enough of the nutrients the body needs to be healthy) caused by being unable to eat.
  • Dehydration (not getting the amount of water the body needs to be healthy) caused by being unable to drink.
  • Tooth decay and gum disease.

Oral complications may be caused by the treatment itself (directly) or by side effects of the treatment (indirectly).

Radiation therapy can directly damage oral tissue, salivary glands, and bone. Areas treated may scar or waste away. Total-body radiation can cause permanent damage to the salivary glands. This can change the way foods taste and cause dry mouth.

Slow healing and infection are indirect complications of cancer treatment. Both chemotherapy and radiation therapy can stop cells from dividing and slow the healing process in the mouth. Chemotherapy may decrease the number of white blood cells and weaken the immune system (the organs and cells that fight infection and disease). This makes it easier to get an infection.

Complications may be acute (short-term) or chronic (long-lasting).

Acute complications are ones that occur during treatment and then go away. Chemotherapy usually causes acute complications that heal after treatment ends.

Chronic complications are ones that continue or appear months to years after treatment ends. Radiation can cause acute complications but may also cause permanent tissue damage that puts you at a lifelong risk of oral complications. The following chronic complications may continue after radiation therapy to the head or neck has ended:

  • Dry mouth.
  • Tooth decay.
  • Infections.
  • Taste changes.
  • Problems in the mouth and jaw caused by loss of tissue and bone.
  • Problems in the mouth and jaw caused by the growth of benign tumors in the skin and muscle.

Oral surgery or other dental work can cause problems in patients who have had radiation therapy to the head or neck. Make sure that your dentist knows your health history and the cancer treatments you received.

Preventing and Treating Oral Complications Before Chemotherapy or Radiation Therapy Begins

Finding and treating oral problems before cancer treatment begins can prevent oral complications or make them less severe.

Problems such as cavities, broken teeth, loose crowns or fillings, and gum disease can get worse or cause problems during cancer treatment. Bacteria live in the mouth and may cause an infection when the immune system is not working well or when white blood cell counts are low. If dental problems are treated before cancer treatments begin, there may be fewer or milder oral complications.

Prevention of oral complications includes a healthy diet, good oral care, and dental checkups.

Ways to prevent oral complications include the following:

  • Eat a well-balanced diet. Healthy eating can help the body stand the stress of cancer treatment, help keep up your energy, fight infection, and rebuild tissue.
  • Keep your mouth and teeth clean. This helps prevent cavities, mouth sores, and infections.
  • Have a complete oral health exam.

    Your dentist should be part of your cancer care team. It is important to choose a dentist who has experience treating patients with oral complications of cancer treatment. A checkup of your oral health at least a month before cancer treatment begins usually allows enough time for the mouth to heal if any dental work is needed. The dentist will treat teeth that have a risk of infection or decay. This will help avoid the need for dental treatments during cancer treatment. Preventive care may help lessen dry mouth, which is a common complication of radiation therapy to the head or neck.

    A preventive oral health exam will check for the following:

    • Mouth sores or infections.
    • Tooth decay.
    • Gum disease.
    • Dentures that do not fit well.
    • Problems moving the jaw.
    • Problems with the salivary glands.

Patients receiving high-dose chemotherapy, stem cell transplant, or radiation therapy should have an oral care plan in place before treatment begins.

The goal of the oral care plan is to find and treat oral disease that may cause complications during treatment and to continue oral care during treatment and recovery. Different oral complications may occur during the different phases of a transplant. Steps can be taken ahead of time to prevent or lessen how severe these side effects will be.

Oral care during radiation therapy will depend on the following:

  • Specific needs of the patient.
  • The radiation dose.
  • The part of the body treated.
  • How long the radiation treatment lasts.
  • Specific complications that occur.

It is important that patients who have head or neck cancer stop smoking.

Continuing to smoke tobacco may slow down recovery. It can also increase the risk that the head or neck cancer will recur or that a second cancer will form.

Managing Oral Complications During and After Chemotherapy or Radiation Therapy

Regular Oral Care

Good dental hygiene may help prevent or decrease complications.

It is important to keep a close watch on oral health during cancer treatment. This helps prevent, find, and treat complications as soon as possible. Keeping the mouth, teeth, and gums clean during and after cancer treatment may help decrease complications such as cavities, mouth sores, and infections.

Everyday oral care for cancer patients includes keeping the mouth clean and being gentle with the tissue lining the mouth.

Everyday oral care during chemotherapy and radiation therapy includes the following:

Brushing teeth

  • Brush teeth and gums with a soft-bristle brush 2 to 3 times a day for 2 to 3 minutes. Be sure to brush the area where the teeth meet the gums and to rinse often.
  • Rinse the toothbrush in hot water every 15 to 30 seconds to soften the bristles, if needed.
  • Use a foam brush only if a soft-bristle brush cannot be used. Brush 2 to 3 times a day and use an antibacterial rinse. Rinse often.
  • Let the toothbrush air-dry between brushings.
  • Use a fluoride toothpaste with a mild taste. Flavoring may irritate the mouth, especially mint flavoring.
  • If toothpaste irritates your mouth, brush with a mixture of 1/4 teaspoon of salt added to 1 cup of water.


  • Use a rinse every 2 hours to decrease soreness in the mouth. Dissolve 1/4 teaspoon of salt and 1/4 teaspoon of baking soda in 1 quart of water.
  • An antibacterial rinse may be used 2 to 4 times a day for gum disease. Rinse for 1 to 2 minutes.
  • If dry mouth occurs, rinsing may not be enough to clean the teeth after a meal. Brushing and flossing may be needed.


  • Floss gently once a day.

Lip care

  • Use lip care products, such as cream with lanolin, to prevent drying and cracking.

Denture care

  • Brush and rinse dentures every day. Use a soft-bristle toothbrush or one made for cleaning dentures.
  • Clean with a denture cleaner recommended by your dentist.
  • Keep dentures moist when not being worn. Place them in water or a denture soaking solution recommended by your dentist. Do not use hot water, which can cause the denture to lose its shape.

For special oral care during high-dose chemotherapy and stem cell transplant, see the Managing Oral Complications of High-Dose Chemotherapy and/or Stem Cell Transplant section of this summary.

Oral Mucositis

Oral mucositis is an inflammation of mucous membranes in the mouth.

The terms "oral mucositis" and "stomatitis" are often used in place of each other, but they are different.

  • Oral mucositis is an inflammation of mucous membranes in the mouth. It usually appears as red, burn-like sores or as ulcer -like sores in the mouth.
  • Stomatitis is an inflammation of mucous membranes and other tissues in the mouth. These include the gums, tongue, roof and floor of the mouth, and the inside of the lips and cheeks.

Mucositis may be caused by either radiation therapy or chemotherapy.

  • Mucositis caused by chemotherapy will heal by itself, usually in 2 to 4 weeks if there is no infection.
  • Mucositis caused by radiation therapy usually lasts 6 to 8 weeks, depending on how long the treatment was.
  • In patients receiving high-dose chemotherapy or chemoradiation for stem cell transplant: Mucositis usually begins 7 to 10 days after treatment begins, and lasts for about 2 weeks after treatment ends.

Swishing ice chips in the mouth for 30 minutes, beginning 5 minutes before patients receive fluorouracil, may help prevent mucositis. Patients who receive high-dose chemotherapy and stem cell transplant may be given medicine to help prevent mucositis or keep it from lasting as long.

Mucositis may cause the following problems:

  • Pain.
  • Infection.
  • Bleeding, in patients receiving chemotherapy. Patients receiving radiation therapy usually do not have bleeding.
  • Trouble breathing and eating.

Care of mucositis during chemotherapy and radiation therapy includes cleaning the mouth and relieving pain.

Treatment of mucositis caused by either radiation therapy or chemotherapy is about the same. Treatment depends on your white blood cell count and how severe the mucositis is. The following are ways to treat mucositis during chemotherapy, stem cell transplant, or radiation therapy:

Cleaning the mouth

  • Clean your teeth and mouth every 4 hours and at bedtime. Do this more often if the mucositis becomes worse.
  • Use a soft-bristle toothbrush.
  • Replace your toothbrush often.
  • Use lubricating jelly that is water-soluble, to help keep your mouth moist.
  • Use mild rinses or plain water. Frequent rinsing removes pieces of food and bacteria from the mouth, prevents crusting of sores, and moistens and soothes sore gums and the lining of the mouth.
  • If mouth sores begin to crust over, the following rinse may be used:
    • Three percent hydrogen peroxide mixed with an equal amount of water or saltwater. To make a saltwater mixture, put 1/4 teaspoon of salt in 1 cup of water.
    This should not be used for more than 2 days because it will keep mucositis from healing.

Relieving mucositis pain

  • Try topical medicines for pain. Rinse your mouth before putting the medicine on the gums or lining of the mouth. Wipe mouth and teeth gently with wet gauze dipped in saltwater to remove pieces of food.
  • Painkillers may help when topical medicines do not. Nonsteroidal anti-inflammatory drugs (NSAIDS, aspirin -type painkillers) should not be used by patients receiving chemotherapy because they increase the risk of bleeding.
  • Zinc supplements taken during radiation therapy may help treat pain caused by mucositis as well as dermatitis (inflammation of the skin).
  • Povidone-iodine mouthwash that does not contain alcohol may help delay or decrease mucositis caused by radiation therapy.

See the Pain section of this summary for more information on pain control.


There can be many causes of oral pain in cancer patients.

A cancer patient's pain may come from the following:

  • The cancer.
  • Side effects of cancer treatments.
  • Other medical conditions not related to the cancer.

Because there can be many causes of oral pain, a careful diagnosis is important. This may include:

  • A medical history.
  • Physical and dental exams.
  • X-rays of the teeth.

Oral pain in cancer patients may be caused by the cancer.

Cancer can cause pain in different ways:

  • The tumor presses on nearby areas as it grows and affects nerves and causes inflammation.
  • Leukemias and lymphomas, which spread through the body and may affect sensitive areas in the mouth. Multiple myeloma can affect the teeth.
  • Brain tumors may cause headaches.
  • Cancer may spread to the head and neck from other parts of the body and cause oral pain.
  • With some cancers, pain may be felt in parts of the body not near the cancer. This is called referred pain. Tumors of the nose, throat, and lungs can cause referred pain in the mouth or jaw.

Oral pain may be a side effect of treatments.

Oral mucositis is the most common side effect of radiation therapy and chemotherapy. Pain in the mucous membranes often continues for a while even after the mucositis is healed.

Surgery may damage bone, nerves, or tissue and may cause pain. Bisphosphonates, drugs taken to treat bone pain, sometimes cause bone to break down. This is most common after a dental procedure such as having a tooth pulled. (See the Oral Complications Not Related to Chemotherapy or Radiation Therapy section of this summary for more information.)

Patients who have transplants may develop graft-versus-host-disease (GVHD). This can cause inflammation of the mucous membranes and joint pain. (See the Managing Oral Complications of High-Dose Chemotherapy and/or Stem Cell Transplant section of this summary for more information).

Certain anticancer drugs can cause oral pain.

If an anticancer drug is causing pain, stopping the drug usually stops the pain. Because there may be many causes of oral pain during cancer treatment, a careful diagnosis is important. This may include a medical history, physical and dental exams, and x-rays of the teeth.

Some patients may have sensitive teeth weeks or months after chemotherapy has ended. Fluoride treatments or toothpaste for sensitive teeth may relieve the discomfort.

Teeth grinding may cause pain in the teeth or jaw muscles.

Pain in the teeth or jaw muscles may occur in patients who grind their teeth or clench their jaws, often because of stress or not being able to sleep. Treatment may include muscle relaxers, drugs to treat anxiety, physical therapy (moist heat, massage, and stretching), and mouth guards to wear while sleeping.

Pain control helps improve the patient's quality of life.

Oral and facial pain can affect eating, talking, and many other activities that involve the head, neck, mouth, and throat. Most patients with head and neck cancers have pain. The doctor may ask the patient to rate the pain using a rating system. This may be on a scale from 0 to 10, with 10 being the worst. The level of pain felt is affected by many different things. It's important for patients to talk with their doctors about pain.

Pain that is not controlled can affect all areas of the patient's life. Pain may cause feelings of anxiety and depression, and may prevent the patient from working or enjoying everyday life with friends and family. Pain may also slow the recovery from cancer or lead to new physical problems. Controlling cancer pain can help the patient enjoy normal routines and a better quality of life.

For oral mucositis pain, topical treatments are usually used. See the Oral Mucositis section of this summary for information on relieving oral mucositis pain.

Other pain medicines may be also be used. Sometimes, more than one pain medicine is needed. Muscle relaxers and medicines for anxiety or depression or to prevent seizures may help some patients. For severe pain, opioids may be prescribed.

Non-drug treatments may also help, including the following:

  • Physical therapy.
  • TENS (transcutaneous electrical nerve stimulation).
  • Applying cold or heat.
  • Hypnosis.
  • Acupuncture. (See the PDQ summary on Acupuncture.)
  • Distraction.
  • Relaxation therapy or imagery.
  • Cognitive behavioral therapy.
  • Music or drama therapy.
  • Counseling.


Damage to the lining of the mouth and a weakened immune system make it easier for infection to occur.

Oral mucositis breaks down the lining of the mouth, which lets bacteria and viruses get into the blood. When the immune system is weakened by chemotherapy, even good bacteria in the mouth can cause infections. Germs picked up from the hospital or other places may also cause infections.

As the white blood cell count gets lower, infections may occur more often and become more serious. Patients who have low white blood cell counts for a long time have a higher risk of serious infections. Dry mouth, which is common during radiation therapy to the head and neck, may also raise the risk of infections in the mouth.

Dental care given before chemotherapy and radiation therapy are started can lower the risk of infections in the mouth, teeth, or gums.

Infections may be caused by bacteria, a fungus, or a virus.

Bacterial infections

Treatment of bacterial infections in patients who have gum disease and receive high-dose chemotherapy may include the following:

  • Using medicated and peroxide mouth rinses.
  • Brushing and flossing.
  • Wearing dentures as little as possible.

Fungal infections

The mouth normally contains fungi that can live on or in the oral cavity without causing any problems. However, an overgrowth (too much fungi) in the mouth can be serious and should be treated.

Antibiotics and steroid drugs are often used when a patient receiving chemotherapy has a low white blood cell count. These drugs change the balance of bacteria in the mouth, making it easier for a fungal overgrowth to occur. Also, fungal infections are common in patients treated with radiation therapy. Patients receiving cancer treatment may be given drugs to help prevent fungal infections from occurring.

Candidiasis is a type of fungal infection that is common in patients receiving both chemotherapy and radiation therapy. Symptoms may include a burning pain and taste changes. Treatment of fungal infections in the lining of the mouth only may include mouthwashes and lozenges that contain antifungal drugs. An antifungal rinse should be used to soak dentures and dental devices and to rinse the mouth. Drugs may be used to when rinses and lozenges do not get rid of the fungal infection. Drugs are sometimes used to prevent fungal infections.

Viral infections

Patients receiving chemotherapy, especially those with immune systems weakened by stem cell transplant, have an increased risk of viral infections. Herpesvirus infections and other viruses that are latent (present in the body but not active or causing symptoms) may flare up. Finding and treating the infections early is important. Giving antiviral drugs before treatment starts can lower the risk of viral infections.


Bleeding may occur when anticancer drugs make the blood less able to clot.

High-dose chemotherapy and stem cell transplants can cause a lower-than-normal number of platelets in the blood. This can cause problems with the body's blood clotting process. Bleeding may be mild (small red spots on the lips, soft palate, or bottom of the mouth) or severe, especially at the gum line and from ulcers in the mouth. Areas of gum disease may bleed on their own or when irritated by eating, brushing, or flossing. When platelet counts are very low, blood may ooze from the gums.

Most patients can safely brush and floss while blood counts are low.

Continuing regular oral care will help prevent infections that can make bleeding problems worse. Your dentist or medical doctor can explain how to treat bleeding and safely keep your mouth clean when platelet counts are low.

Treatment for bleeding during chemotherapy may include the following:

  • Medicines to reduce blood flow and help clots form.
  • Topical products that cover and seal bleeding areas.
  • Rinsing with a mixture of saltwater and 3% hydrogen peroxide. (The mixture should have 2 or 3 times the amount of saltwater than hydrogen peroxide.) To make the saltwater mixture, put 1/4 teaspoon of salt in 1 cup of water. This helps clean wounds in the mouth. Rinse carefully so clots are not disturbed.

Dry Mouth

Dry mouth (xerostomia) occurs when the salivary glands don't make enough saliva.

Saliva is made by salivary glands. Saliva is needed for taste, swallowing, and speech. It helps prevent infection and tooth decay by cleaning off the teeth and gums and preventing too much acid in the mouth.

Radiation therapy can damage salivary glands and cause them to make too little saliva. Some types of chemotherapy used for stem cell transplant may also damage salivary glands.

When there is not enough saliva, the mouth gets dry and uncomfortable. This condition is called dry mouth (xerostomia). The risk of tooth decay, gum disease, and infection increases, and your quality of life suffers.

Symptoms of dry mouth include the following:

  • Thick, stringy saliva.
  • Increased thirst.
  • Changes in taste, swallowing, or speech.
  • A sore or burning feeling (especially on the tongue).
  • Cuts or cracks in the lips or at the corners of the mouth.
  • Changes in the surface of the tongue.
  • Problems wearing dentures.

Salivary glands usually return to normal after chemotherapy ends.

Dry mouth caused by chemotherapy for stem cell transplant is usually temporary. The salivary glands often recover 2 to 3 months after chemotherapy ends.

Salivary glands may not recover completely after radiation therapy ends.

The amount of saliva made by the salivary glands usually starts to decrease within 1 week after starting radiation therapy to the head or neck. It continues to decrease as treatment goes on. How severe the dryness is depends on the dose of radiation and the number of salivary glands that receive radiation.

Salivary glands may partly recover during the first year after radiation therapy. However, recovery is usually not complete, especially if the salivary glands received direct radiation. Salivary glands that did not receive radiation may start making more saliva to make up for the loss of saliva from the damaged glands.

Careful oral hygiene can help prevent mouth sores, gum disease, and tooth decay caused by dry mouth.

Care of dry mouth may include the following:

  • Clean the mouth and teeth at least 4 times a day.
  • Floss once a day.
  • Brush with a fluoride toothpaste.
  • Apply fluoride gel once a day at bedtime, after cleaning the teeth.
  • Rinse 4 to 6 times a day with a mixture of salt and baking soda (mix ½ teaspoon salt and ½ teaspoon baking soda in 1 cup of warm water).
  • Avoid foods and liquids that have a lot of sugar in them.
  • Sip water often to relieve mouth dryness.

A dentist may give the following treatments:

  • Rinses to replace minerals in the teeth.
  • Rinses to fight infection in the mouth.
  • Saliva substitutes or medicines that help the salivary glands make more saliva.
  • Fluoride treatments to prevent tooth decay.

Acupuncture may also help relieve dry mouth.

Tooth Decay

Dry mouth and changes in the balance of bacteria in the mouth increase the risk of tooth decay (cavities). Careful oral hygiene and regular care by a dentist can help prevent cavities. See the Regular Oral Care section of this summary for more information.

Taste Changes

Changes in taste (dysguesia) are common during chemotherapy and radiation therapy.

Changes in the sense of taste is a common side effect of both chemotherapy and head or neck radiation therapy. Taste changes can be caused by damage to the taste buds, dry mouth, infection, or dental problems. Foods may seem to have no taste or may not taste the way they did before cancer treatment. Radiation may cause a change in sweet, sour, bitter, and salty tastes. Chemotherapy drugs may cause an unpleasant taste.

In most patients receiving chemotherapy and in some patients receiving radiation therapy, taste returns to normal a few months after treatment ends. However, for many radiation therapy patients, the change is permanent. In others, the taste buds may recover 6 to 8 weeks or more after radiation therapy ends. Zinc sulfate supplements may help some patients recover their sense of taste.


Cancer patients who are receiving high-dose chemotherapy or radiation therapy often feel fatigue (a lack of energy). This can be caused by either the cancer or its treatment. Some patients may have problems sleeping. Patients may feel too tired for regular oral care, which may further increase the risk for mouth ulcers, infection, and pain. For more information, see Cancer Fatigue.


Loss of appetite can lead to malnutrition.

Patients treated for head and neck cancers have a high risk of malnutrition. The cancer itself, poor diet before diagnosis, and complications from surgery, radiation therapy, and chemotherapy can lead to nutrition problems. Patients may lose the desire to eat because of nausea, vomiting, trouble swallowing, sores in the mouth, or dry mouth. When eating causes discomfort or pain, the patient's quality of life and nutritional well-being suffer. The following may help patients with cancer meet their nutrition needs:

  • Serve food chopped, ground, or blended, to shorten the amount of time it needs to stay in the mouth before being swallowed.
  • Eat between-meal snacks to add calories and nutrients.
  • Eat foods high in calories and protein.
  • Take supplements to get vitamins, minerals, and calories.

Meeting with a nutrition counselor may help during and after treatment.

Nutrition support may include liquid diets and tube feeding.

Many patients treated for head and neck cancers who receive radiation therapy only are able to eat soft foods. As treatment continues, most patients will add or switch to high-calorie, high-protein liquids to meet their nutrition needs. Some patients may need to receive the liquids through a tube that is inserted into the stomach or small intestine. Almost all patients who receive chemotherapy and head or neck radiation therapy at the same time will need tube feedings within 3 to 4 weeks. Studies show that patients do better if they begin these feedings at the start of treatment, before weight loss occurs.

Normal eating by mouth can begin again when treatment is finished and the area that received radiation is healed. A team that includes a speech and swallowing therapist can help the patients with the return to normal eating. Tube feedings are decreased as eating by mouth increases, and are stopped when you are able to get enough nutrients by mouth. Although most patients will once again be able to eat solid foods, many will have lasting complications such as taste changes, dry mouth, and trouble swallowing.

Mouth and Jaw Stiffness

Treatment for head and neck cancers may affect the ability to move the jaws, mouth, neck, and tongue. There may be problems with swallowing. Stiffness may be caused by:

  • Oral surgery.
  • Late effects of radiation therapy. An overgrowth of fibrous tissue (fibrosis) in the skin, mucous membranes, muscle, and joints of the jaw may occur after radiation therapy has ended.
  • Stress caused by the cancer and its treatment.

Jaw stiffness may lead to serious health problems, including:

  • Malnutrition and weight loss from being unable to eat normally.
  • Slower healing and recovery from poor nutrition.
  • Dental problems from being unable to clean the teeth and gums well and have dental treatments.
  • Weakened jaw muscles from not using them.
  • Emotional problems from avoiding social contact with others because of trouble speaking and eating.

The risk of having jaw stiffness from radiation therapy increases with higher doses of radiation and with repeated radiation treatments. The stiffness usually begins around the time the radiation treatments end. It may get worse over time, stay the same, or get somewhat better on its own. Treatment should begin as soon as possible to keep the condition from getting worse or becoming permanent. Treatment may include the following

  • Medical devices for the mouth.
  • Pain treatments.
  • Medicine to relax muscles.
  • Jaw exercises.
  • Medicine to treat depression.

Swallowing Problems

Pain during swallowing and being unable to swallow (dysphagia) are common in cancer patients before, during, and after treatment.

Swallowing problems are common in patients who have head and neck cancers. Cancer treatment side effects such as oral mucositis, dry mouth, skin damage from radiation, infections, and graft-versus-host-disease (GVHD) may all cause problems with swallowing.

Trouble swallowing increases the risk of other complications.

Other complications can develop from being unable to swallow and these can further decrease the patient's quality of life:

  • Pneumonia and other respiratory problems: Patients who have trouble swallowing may aspirate (inhale food or liquids into the lung) when trying to eat or drink. Aspiration can lead to serious conditions, including pneumonia and respiratory failure.
  • Poor nutrition: Being unable to swallow normally makes it hard to eat well. Malnutrition occurs when the body doesn't get all the nutrients needed for health. Wounds heal slowly and the body is less able to fight off infections.
  • Need for tube feeding: A patient who is not able to take in enough food by mouth may be fed through a tube. The healthcare team and a registered dietitian can explain the benefits and risks of tube feeding for patients who have swallowing problems.
  • Side effects of pain medicine: Opioids used to treat painful swallowing may cause dry mouth and constipation.
  • Emotional problems: Being unable to eat, drink, and speak normally may cause depression and the desire to avoid other people.

Whether radiation therapy will affect swallowing depends on several factors.

The following may affect the risk of swallowing problems after radiation therapy:

  • Total dose and schedule of radiation therapy. Higher doses over a shorter time often have more side effects.
  • The way the radiation is given. Some types of radiation cause less damage to healthy tissue.
  • Whether chemotherapy is given at the same time. The risk of side effects is increased if both are given.
  • The patient's genetic makeup.
  • Whether the patient is taking any food by mouth or only by tube feeding.
  • Whether the patient smokes.
  • How well the patient copes with problems.

Swallowing problems sometimes go away after treatment

Some side effects go away within 3 months after the end of treatment, and patients are able to swallow normally again. However, some treatments can cause permanent damage or late effects. Late effects are health problems that occur long after treatment has ended. Conditions that may cause permanent swallowing problems or late effects include:

  • Damaged blood vessels.
  • Wasting away of tissue in the treated areas.
  • Lymphedema (buildup of lymph in the body).
  • Overgrowth of fibrous tissue in head or neck areas, which may lead to jaw stiffness.
  • Chronic dry mouth.
  • Infections.

Swallowing problems are managed by a team of experts.

The oncologist works with other health care experts who specialize in treating head and neck cancers and the oral complications of cancer treatment. These specialists may include the following:

  • Speech therapist: A speech therapist can assess how well the patient is swallowing and give the patient swallowing therapy and information to better understand the problem.
  • Dietitian: A dietitian can help plan a safe way for the patient to receive the nutrition needed for health while swallowing is a problem.
  • Dental specialist: Replace missing teeth and damaged area of the mouth with artificial devices to help swallowing.
  • Psychologist: For patients who are having a hard time adjusting to being unable to swallow and eat normally, psychological counseling may help.

Tissue and Bone Loss

Radiation therapy can destroy very small blood vessels within the bone. This can kill bone tissue and lead to bone fractures or infection. Radiation can also kill tissue in the mouth. Ulcers may form, grow, and cause pain, loss of feeling, or infection.

Preventive care can make tissue and bone loss less severe.

The following may help prevent and treat tissue and bone loss:

  • Eat a well-balanced diet.
  • Wear removable dentures or devices as little as possible.
  • Don't smoke.
  • Don't drink alcohol.
  • Use topical antibiotics.
  • Use painkillers as prescribed.
  • Surgery to remove dead bone or to rebuild bones of the mouth and jaw.
  • Hyperbaric oxygen therapy (a method that uses oxygen under pressure to help wounds heal).

See the PDQ summary on Nutrition in Cancer Care for more information about managing mouth sores, dry mouth, and taste changes.

Managing Oral Complications of High-Dose Chemotherapy and / or Stem Cell Transplant

Patients who receive transplants have an increased risk of graft-versus-host disease.

Graft-versus-host disease (GVHD) occurs when your tissue reacts to bone marrow or stem cells that come from a donor. Symptoms of oral GVHD include the following:

  • Sores that are red and have ulcers, which appear in the mouth 2 to 3 weeks after the transplant.
  • Dry mouth.
  • Pain from spices, alcohol, or flavoring (such as mint in toothpaste).
  • Swallowing problems.
  • A feeling of tightness in the skin or in the lining of the mouth.
  • Taste changes.

It's important to have these symptoms treated because they can lead to weight loss or malnutrition. Treatment of oral GVHD may include the following:

  • Topical rinses, gels, creams, or powders.
  • Antifungal drugs taken by mouth or injection.
  • Psoralen and ultraviolet A (PUVA) therapy.
  • Drugs that help the salivary glands make more saliva.
  • Fluoride treatments.
  • Treatments to replace minerals lost from teeth by acids in the mouth.

Oral devices need special care during high-dose chemotherapy and/or stem cell transplant.

The following can help in the care and use of dentures, braces, and other oral devices during high-dose chemotherapy or stem cell transplant:

  • Have brackets, wires, and retainers removed before high-dose chemotherapy begins.
  • Wear dentures only when eating during the first 3 to 4 weeks after the transplant.
  • Brush dentures twice a day and rinsing them well.
  • Soak dentures in an antibacterial solution when they are not being worn.
  • Clean denture soaking cups and changing denture soaking solution every day.
  • Remove dentures or other oral devices when cleaning your mouth.
  • Continue your regular oral care 3 or 4 times a day with dentures or other devices out of the mouth.
  • If you have mouth sores, avoid using removable oral devices until the sores have healed.

Care of the teeth and gums is important during chemotherapy or stem cell transplant.

Talk to your medical doctor or dentist about the best way to take care of your mouth during high-dose chemotherapy and stem cell transplant. Careful brushing and flossing may help prevent infection of oral tissues. The following may help prevent infection and relieve discomfort of oral in tissues:

  • Brush teeth with a soft-bristle brush 2 to 3 times a day. Be sure to brush the area where the teeth meet the gums.
  • Rinse the toothbrush in hot water every 15 to 30 seconds to keep the bristles soft.
  • Rinse your mouth 3 or 4 times while brushing.
  • Avoid rinses that have alcohol in them.
  • Use a mild-tasting toothpaste.
  • Let the toothbrush air-dry between uses.
  • Floss according to your medical doctor's or dentist's directions.
  • Clean the mouth after meals.
  • Use foam swabs to clean the tongue and roof of the mouth.
  • Avoid the following:
    • Foods that are spicy or acidic.
    • "Hard" foods that could irritate or break the skin in your mouth, such as chips.
    • Hot foods and drinks.

Medicines and ice may be used to prevent and treat mucositis from stem cell transplant.

Medicines may be given to help prevent mouth sores or help the mouth heal faster if it is damaged by chemotherapy or radiation therapy. Also, holding ice chips in the mouth during high-dose chemotherapy, may help prevent mouth sores.

Dental treatments may be put off until the patient's immune system returns to normal.

Regular dental treatments, including cleaning and polishing, should wait until the transplant patient's immune system returns to normal. The immune system can take 6 to 12 months to recover after high-dose chemotherapy and stem cell transplant. During this time, the risk of oral complications is high. If dental treatments are needed, antibiotics and supportive care are given.

Supportive care before oral procedures may include giving antibiotics or immunoglobulin G, adjusting steroid doses, and/or platelet transfusion.

Oral Complications in Second Cancers

Cancer survivors who received chemotherapy or a transplant or who underwent radiation therapy are at risk of developing a second cancer later in life. Oral squamous cell cancer is the most common second oral cancer in transplant patients. The lips and tongue are the areas that are affected most often.

Second cancers are more common in patients treated for leukemia or lymphoma, Multiple myeloma patients who received a stem cell transplant using their own stem cells sometimes develop an oral plasmacytoma.

Patients who received a transplant should see a doctor if they have swollen lymph nodes or lumps in soft tissue areas. This could be a sign of a second cancer.

Oral Complications Not Related to Chemotherapy or Radiation Therapy

Certain drugs used to treat cancer and other bone problems are linked to bone loss in the mouth.

Some drugs break down bone tissue in the mouth. This is called osteonecrosis of the jaw (ONJ). ONJ can also cause infection. Symptoms include pain and inflamed lesions in the mouth, where areas of damaged bone may show.

Drugs that may cause ONJ include the following:

  • Bisphosphonates: Drugs given to some patients whose cancer has spread to the bones. They are used to decrease pain and the risk of broken bones. Bisphosphonates are also used to treat hypercalcemia (too much calcium in the blood). Bisphosphonates commonly used include zoledronic acid, pamidronate, and alendronate.
  • Denosumab: A drug used to prevent or treat certain bone problems. Denosumab is a type of monoclonal antibody.
  • Angiogenesis inhibitors: Drugs or substances that keep new blood vessels from forming. In cancer treatment, angiogenesis inhibitors may prevent the growth of new blood vessels that tumors need to grow. Some of the angiogenesis inhibitors that may cause ONJ are bevacizumab, sunitinib, and sorafenib.

It's important for the health care team to know if a patient has been treated with these drugs. Cancer that has spread to the jawbone can look like ONJ. A biopsy may be needed to find out the cause of the ONJ.

ONJ is not a common condition. It occurs more often in patients who receive bisphosphonates or denosumab by injection than in patients who take them by mouth. Taking bisphosphonates, denosumab, or angiogenesis inhibitors increases the risk of ONJ. The risk of ONJ is much greater when angiogenesis inhibitors and bisphosphonates are used together.

The following may also increase the risk of ONJ:

  • Having teeth removed.
  • Wearing dentures that do not fit well.
  • Having multiple myeloma.

Patients with bone metastases may decrease their risk of ONJ by getting screened and treated for dental problems before bisphosphonate or denosumab therapy is started.

Treatment of ONJ usually includes treating the infection and good dental hygiene.

Treatment of ONJ may include the following:

  • Removing the infected tissue, which may include bone. Laser surgery may be used.
  • Smoothing sharp edges of exposed bone.
  • Using antibiotics to fight infection.
  • Using medicated mouth rinses.
  • Using pain medicine.

During treatment for ONJ, you should continue to brush and floss after meals to keep your mouth very clean. It is best to avoid tobacco use while ONJ is healing.

You and your doctor can decide whether you should stop using medicines that cause ONJ, based on the effect it would have on your general health.

Oral Complications and Social Problems

The social problems related to oral complications can be the hardest problems for cancer patients to cope with. Oral complications affect eating and speaking and may make you unable or unwilling to take part in mealtimes or to dine out. Patients may become frustrated, withdrawn, or depressed, and they may avoid other people. Some drugs that are used to treat depression cannot be used because they can make oral complications worse. See the following PDQ summaries for more information:

  • Adjustment to Cancer: Anxiety and Distress
  • Depression

Education, supportive care, and the treatment of symptoms are important for patients who have mouth problems that are related to cancer treatment. Patients are watched closely for pain, ability to cope, and response to treatment. Supportive care from health care providers and family can help the patient cope with cancer and its complications.

Oral Complications of Chemotherapy and Radiation Therapy in Children

Children who received high-dose chemotherapy or radiation therapy to the head and neck may not have normal dental growth and development. New teeth may appear late or not at all, and tooth size may be smaller than normal. The head and face may not develop fully. The changes are usually the same on both sides of the head and are not always noticeable.

Orthodontic treatment for patients with these dental growth and development side effects is being studied.

Changes to This Summary (03 / 06 / 2024)

The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.

The title of this summary was changed to match the health professional version and the metadata was updated.

About This PDQ Summary

About PDQ

Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.

PDQ is a service of the NCI. The NCI is part of the National Institutes of Health (NIH). NIH is the federal government's center of biomedical research. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH.

Purpose of This Summary

This PDQ cancer information summary has current information about the causes and treatment of oral complications of cancer therapies. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.

Reviewers and Updates

Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Updated") is the date of the most recent change.

The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Supportive and Palliative Care Editorial Board.

Clinical Trial Information

A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

Clinical trials can be found online at NCI's website. For more information, call the Cancer Information Service (CIS), NCI's contact center, at 1-800-4-CANCER (1-800-422-6237).

Permission to Use This Summary

PDQ is a registered trademark. The content of PDQ documents can be used freely as text. It cannot be identified as an NCI PDQ cancer information summary unless the whole summary is shown and it is updated regularly. However, a user would be allowed to write a sentence such as "NCI's PDQ cancer information summary about breast cancer prevention states the risks in the following way: [include excerpt from the summary]."

The best way to cite this PDQ summary is:

PDQ® Supportive and Palliative Care Editorial Board. PDQ Oral Complications of Cancer Therapies. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: Accessed <MM/DD/YYYY>. [PMID: 26389169]

Images in this summary are used with permission of the author(s), artist, and/or publisher for use in the PDQ summaries only. If you want to use an image from a PDQ summary and you are not using the whole summary, you must get permission from the owner. It cannot be given by the National Cancer Institute. Information about using the images in this summary, along with many other images related to cancer can be found in Visuals Online. Visuals Online is a collection of more than 3,000 scientific images.


The information in these summaries should not be used to make decisions about insurance reimbursement. More information on insurance coverage is available on on the Managing Cancer Care page.

Contact Us

More information about contacting us or receiving help with the website can be found on our Contact Us for Help page. Questions can also be submitted to through the website's E-mail Us.

Last Revised: 2024-03-06

If you want to know more about cancer and how it is treated, or if you wish to know about clinical trials for your type of cancer, you can call the NCI's Cancer Information Service at 1-800-422-6237, toll free. A trained information specialist can talk with you and answer your questions.

This information does not replace the advice of a doctor. Healthwise, Incorporated, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Learn how we develop our content.