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Stomatitis From Cancer Treatment: Care Instructions

Inside of the lower lip, showing stomatitis sores


Stomatitis, also called oral mucositis, is swelling and redness of the lining of your mouth. It can cause painful sores that can make it hard for you to eat, drink, or swallow. It's a common side effect of cancer treatments such as some chemotherapy and radiation. Your doctor may prescribe pain medicines or mouth rinses to treat it.

Having stomatitis can increase the risk of getting an infection in your mouth. This could be caused by bacteria, a virus, or a yeast infection. Medicines can treat this problem.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

How can you care for yourself at home?

  • Be safe with medicines. Read and follow all instructions on the label.
    • If the doctor gave you a prescription medicine for pain, take it as prescribed.
    • If you are not taking a prescription pain medicine, ask your doctor if you can take an over-the-counter medicine.
  • If your doctor prescribed antibiotics or antifungals, take them as directed. Do not stop taking them just because you feel better. You need to take the full course of medicine.
  • Make a rinse to keep your mouth from getting dry. Add 1 teaspoon (5 millilitres) baking soda and ½ teaspoon (2.5 millilitres) salt to 4 cups (1 litre) of water. Use it to rinse your mouth 4 to 6 times each day. Spit out the rinse. Do not swallow it.
  • Use prescription mouth rinses as prescribed. Ask your doctor if you can freeze the mouth rinse in an ice cube tray. Sucking on a frozen cube of the mouth rinse can help ease the pain.
  • Eat soft foods such as mashed potatoes and other cooked vegetables, noodles, applesauce, clear broth soups, yogurt, and cottage cheese. You can get extra protein by adding protein powder to milkshakes or breakfast drinks. Avoid spicy, crunchy, salty, or sugary foods.
  • Try eating cold foods such as ice cream or frozen yogurt.
  • Drink plenty of fluids to prevent dehydration. Drinking through a straw may help with pain. Avoid high-acid juices such as orange, grapefruit, and cranberry juice. They may make your mouth hurt.
  • Practice good oral hygiene. Use a very soft toothbrush to brush your teeth. You could also use a soft cloth.

When should you call for help?

Call your doctor or nurse advice line now or seek immediate medical care if:

  • You can't eat or drink.
  • You have new or worse pain.
  • You have a fever.

Watch closely for changes in your health, and be sure to contact your doctor or nurse advice line if:

  • You do not get better as expected.

Where can you learn more?

Go to

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Care instructions adapted under license by your healthcare professional. If you have questions about a medical condition or this instruction, always ask your healthcare professional. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.