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Oral Complications of Chemotherapy and Head/Neck Radiation (PDQ®)

Managing Oral Complications During and After Chemotherapy or Radiation Therapy

Key Points for This Section

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:

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

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:

See the Other Treatments for Pain section of the PDQ summary on Pain for more information.


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. (See the PDQ summary on Fatigue for more information.)


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.

  • Updated: April 24, 2014