Mouth Care During Your Cancer Treatment

Time to Read: About 4 minutes

This information explains how to care for your mouth during cancer treatment.

About Mucositis

Some cancer treatments, including radiation therapy to the head and neck, may affect the cells that are in your mouth and digestive tract. This is known as mucositis.

Mucositis can cause redness, swelling, tenderness, and sores on the lining of your mouth, tongue, and lips. You may experience some mouth and throat discomfort that can make it hard to eat or swallow. These symptoms may begin 3 to 10 days after treatment starts. How quickly they go away depends on your immune system and the treatment you’re receiving.

Caring for Your Mouth During Your Cancer Treatment

Dental care

Your doctor may tell you to see a dentist before you start cancer treatment. If you need to see your dentist during your treatment, ask them to call your doctor at Memorial Sloan Kettering (MSK) first.


  • Brush your teeth and tongue gently within 30 minutes after eating. Use a small, soft-bristle toothbrush. If your mouth is too sore for a regular soft toothbrush, you can get a supersoft one from a drugstore. Some examples of these are:
    • Biotene® Supersoft Toothbrush
    • Sensodyne® Extra Soft, Gentle Toothbrush
    • Colgate® 360 Sensitive Pro-Relief Toothbrush, Compact Head, Extra Soft
    • Oral-B® Indicator 35 Compact Head Toothbrush, Soft
  • Change your toothbrush every 3 to 4 months or more often if needed.
  • Use a fluoride toothpaste or baking soda with fluoride.
  • If you have a set of dentures, a bridge, or a dental prosthesis, take it out and clean it each time you clean your mouth. You can keep wearing it if it fits well and doesn’t irritate your mouth. Take it out of your mouth while you sleep. If you have any irritation, keep it out of your mouth as much as possible.


Floss your teeth with unwaxed dental floss once daily at bedtime. If you haven’t flossed regularly before treatment, don’t start flossing now.


  • Rinse your mouth every 4 to 6 hours, or more often as needed. Use one of the rinses listed below:
    • One quart (4 cups) of water mixed with 1 teaspoon of salt and 1 teaspoon of baking soda.
    • One quart of water mixed with 1 teaspoon of salt
    • One quart of water mixed with 1 teaspoon of baking soda
    • Water
    • A mouthwash with no alcohol or sugar, such as Biotene® PBF Oral Rinse or BetaCell™ Oral Rinse.
  • Swish the rinse in your mouth and gargle well for 15 to 30 seconds, then spit out the rinse.
  • Don’t use very hot or cold temperatures of mouth rinses.
  • Don’t use mouthwashes that have hydrogen peroxide unless your doctor tells you to.
  • If your nurse told you to irrigate your mouth, you will get other instructions about rinsing.
  • If you’re not eating food orally (by mouth), make sure your mouth is kept clean and moist to avoid mucositis.

Moisturizing your lips

  • Use a lip moisturizer (such as, Aquaphor®, Vaseline®, Eucerin Original®, or A&D® ointment) 4 to 6 times a day to prevent dry lips.
  • Don’t apply lip moisturizers 4 hours before radiation therapy to the head and neck.

Managing Mouth Pain During Your Cancer Treatment

What to avoid

If you have mouth pain during your cancer treatment, you should avoid:

  • Tobacco
  • Alcohol
  • Mouthwash that has alcohol (such as Scope® and Listerine®)
  • Salty foods and foods that contain strong spices (such as pepper, chili powder, horseradish, curry powder, and Tabasco® sauce)
  • Citrus fruits and juices (such as orange, lemon, lime, grapefruit, and pineapple)
  • Tomatoes and tomato sauce
  • Hard, dry, or coarse foods (such as toast, crackers, raw vegetables, potato chips, and pretzels)
  • Very hot or cold foods and liquids

Managing symptoms

About medications

If you have a few small, painful areas, your doctor may prescribe an anesthetic (numbing medication), such as viscous lidocaine 2%. You can apply it to the painful areas using a cotton swab (Q-tip®). Apply it every hour as needed.

If you feel pain in most of your mouth and throat, your doctor may prescribe medication to coat your whole mouth (such as GelClair® or viscous lidocaine 2%). Swish, gargle, and spit out 1 tablespoon of the medication every 3 to 4 hours, up to 8 times a day. Don’t swallow the medication. Don’t eat for 60 minutes after using the medication.

If you still have mouth pain, tell your healthcare provider. They may prescribe other medications for your mucositis.

Trouble swallowing

Here are some suggestions to help make swallowing easier. This will help you take in enough protein and calories during your treatment:

  • If your mouth is dry, rinse it just before eating to moisten it and stimulate your taste buds.
  • Eat warm or cool foods. Don’t eat very hot or very cold foods.
  • Eat soft, moist, bland foods in small bites and chew them well.
  • Use sauces and gravies.
  • Moisten foods with yogurt, milk, soy milk, or water.
  • Dip dry foods in liquids.
  • Blend or purée your food.
  • Avoid things that can irritate your throat such as alcoholic beverages, tart or acidic fruits and juices, spicy foods, pickled foods, and tobacco.
  • Sip plenty of water throughout the day to be sure you have enough liquids. Keep in mind that drinks with sugar (juice, iced tea, and soda) may cause tooth decay. You can drink these during meals, but limit them between meals.

Dry mouth

To manage dry mouth, drink sips of water often throughout the day. You can also use:

  • A spray bottle to squirt water into your mouth
  • Mouth moisturizers (such as Biotene® Oral Balance, Salivart® Oral Moisturizer, Mouth Kote® Dry Mouth Spray)
  • Biotene® Gum
  • A humidifier in the room that you’re in

Trouble eating

You may have trouble eating due to your mouth pain. If you do, here are some suggestions to make sure you’re getting all the nutrients you need.

  • Tell your healthcare provider if you’re not eating well. They may arrange for you to see a dietitian.
  • Drink nutritional supplements such as Carnation® Instant Breakfast and Ensure®.
  • Add protein powders to broths, soups, cereals, and beverages.
  • Eat multiple small meals throughout the day rather than fewer large meals. Try having a small meal every 2 to 3 hours.

Mouth Care for Children

Children should follow the guidelines in this resource. They should also follow the ones listed below.

  • Use a fluoride toothpaste. For children 2 years of age or younger, talk with a dentist or doctor before using fluoride toothpaste.
  • If your child doesn’t have teeth yet, use a washcloth, towelette, or sponge and water to clean their gums after meals and before bed.
  • If your child’s immune system is stable, they should visit the dentist for routine care every 6 months.
  • Talk with Child Life Services to learn how to help your child manage their pain. You can reach them at 833-675-5437 (833-MSK-KIDS).

Call Your Healthcare Provider if You Have:

  • A fever of 100.4 °F (38 °C) or higher
  • New redness, sores, or white patches in your mouth
  • Bleeding of your gums or mouth
  • Trouble swallowing
  • Pain when you swallow
  • Pain that doesn’t get better with pain medication
  • Any questions or concerns 

Last Updated

Thursday, August 19, 2021

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