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Mouth and Throat Problems: Cancer Treatment Side Effects

Young women with cancer having soft food that’s easy to swallow.

If mouth and throat side effects make it difficult to eat, try softer foods. Talk with your doctor about mouth rinses and pain medicine that can help. 

Credit: National Cancer Institute

What causes mouth and throat problems?

Cancer treatments may cause mouth, throat, and dental problems. Radiation therapy to the head and neck may harm the salivary glands and tissues in your mouth and/or make it hard to chew and swallow safely. Some types of chemotherapy and immunotherapy can also harm cells in your mouth, throat, and lips. Drugs used to treat cancer and certain bone problems may also cause oral problems.

What mouth and throat problems may occur?

Mouth and throat problems may include:

When are oral problems serious?

Mouth problems (also called oral problems) are more serious if they interfere with eating and drinking because they can lead to dehydration and/or malnutrition. It’s important to call your doctor or nurse if you have pain in your mouth, lips, or throat that makes it difficult to eat, drink, or sleep or if you have a fever of 100.5 °F (38 °C) or higher.

Ways to prevent mouth and dental problems

Your doctor or nurse may advise you to take these and other steps:

  • Get a dental check-up before starting treatment. Before you start treatment, visit your dentist for a cleaning and check-up. Tell the dentist about your cancer treatment and try to get any dental work completed before starting treatment.
  • Check and clean your mouth daily. Check your mouth every day for sores or white spots. Tell your doctor or nurse as soon as you notice any changes, such as pain or sensitivity. Rinse your mouth throughout the day with a solution of warm water, baking soda, and salt. Ask your nurse to write down the mouth rinse recipe that is recommended for you. Gently brush your teeth, gums, and tongue after each meal and before going to bed at night. Use a very soft toothbrush or cotton swabs. If you are at risk of bleeding, ask if you should floss.

Ways to manage mouth problems and changes in taste

Your health care team may suggest that you take these and other steps to manage these problems:

  • For a sore mouth or throat: Choose foods that are soft, wet, and easy to swallow. Soften dry foods with gravy, sauce, or other liquids. Use a blender to make milkshakes or blend your food to make it easier to swallow. Ask about pain medicine, such as lozenges or sprays that numb your mouth and make eating less painful. Avoid foods and drinks that can irritate your mouth; foods that are crunchy, salty, spicy, or sugary; and alcoholic drinks. Don’t smoke or use tobacco products.
  • For a dry mouth: Drink plenty of liquids because a dry mouth can increase the risk of tooth decay and mouth infections. Keep water handy and sip it often to keep your mouth wet. Suck on ice chips or sugar-free hard candy, have frozen desserts, or chew sugar-free gum. Use a lip balm. Ask about medicines such as saliva substitutes that can coat, protect, and moisten your mouth and throat. Acupuncture may also help with dry mouth.
  • For changes to your sense of taste: Foods may seem to have no taste or may not taste the way they used to or food may not have much taste at all. Radiation therapy may cause a change in sweet, sour, bitter, and salty tastes. Chemotherapy drugs may cause an unpleasant chemical or metallic taste in your mouth. If you have taste changes it may help to try different foods to find ones that taste best to you. Trying cold foods may also help. Here are some more tips to consider:
    • Improving Taste and Smell During Cancer Treatment

      Cancer and its treatment can cause changes in taste or smell that can make it hard to eat. Try our tips to deal with these changes.

      If food tastes bland, marinate foods to improve their flavor or add spices to foods. 
    • If red meat tastes strange, switch to other high-protein foods such as chicken, eggs, fish, peanut butter, turkey, beans, or dairy products.
    • If foods taste salty, bitter, or acidic, try sweetening them.
    • If foods taste metallic, switch to plastic utensils and non-metal cooking dishes.
    • If you have a bad taste in your mouth, try sugar-free lemon drops, gum, or mints.

Talking with your health care team about mouth and throat problems

Prepare for your visit by making a list of questions to ask. Consider adding these questions to your list:

  • When might these problems start to occur? How long might they last?
  • What steps can I take to feel better?
  • What medicines can help?
  • What symptoms or problems should I call the doctor about?
  • What pain medicine and/or mouthwashes could help me?
  • Would you recommend a registered dietitian who I could see to learn about good food choices?
  • For people receiving radiation therapy to the head and neck: Should I take supplements such as zinc, to help my sense of taste come back after treatment?


Listen to tips on how to manage mouth or throat pain caused by cancer treatments such as radiation therapy.
(Type: MP3 | Time: 3:26 | Size: 3.2MB)