It’s vital to work closely with your health care team to manage mouth sores.

Oral mucositis is a serious side effect of some cancer treatments. The term “oral mucositis” refers to mouth sores caused by irritation of the mucosa—the soft tissues that cover the tongue and inside of the mouth. These types of sores aren’t always found just in the mouth. They can also affect the upper part of the throat and other parts of the digestive system.

Not every person with cancer develops mouth sores. Generally, those who do have such sores have had bone marrow transplants or been treated with radiation to the head and neck. The cancer treatments most likely to cause mouth sores include doxorubicin (Doxil and others), capecitabine (Xeloda), cisplatin (Platinol and others), fluorouracil (5-FU), methotrexate (sometimes called amethopterin or MTX), and high-dose chemotherapy given before a bone marrow transplant.

Mouth sores can cause pain and infections that make it difficult to swallow, eat, and drink. For this reason, they can also lead to weight loss for some people. Patients who are unable to eat or drink for a long period of time may need to receive fluids and nutrition through an IV line or a feeding tube, which could require a hospital stay.

Because mouth sores can be very painful, some patients want to take a break from treatment to let the tissues rest. But stopping treatment, even for a short time, may make your treatment less effective.

It is important that you talk with the members of your health care team about how best to manage this side effect, even before cancer treatment begins. If you experience mouth sores, there are medications they can prescribe to reduce pain, infection, and discomfort from mouth sores until you finish your treatment. There are also things you can do on your own to help manage this symptom. Once treatment ends, your mouth sores will gradually fade.

How Mouth Sores Develop

Mouth sores do not develop right away. For the first few days of chemotherapy or radiation, you probably won’t notice any changes in your mouth. However, after three to five days, the soft tissues of the mouth may feel a little warm. There might be some tingling and mild soreness.

Sores may begin to appear within about a week and a half after the start of cancer treatment. Usually, the sores remain until after treatment stops. A week or two after treatment ends, the sores usually begin to heal. Usually, by the third week after treatment stops, the mouth sores and pain disappear. If your treatment has been very aggressive, you may experience more severe mouth sores that last longer. Typical signs and symptoms of mouth sores include shiny, swollen tissues in the mouth and on or under the tongue; red, inflamed patches, sometimes with white spots; sticky mucous or blood in the mouth; a white or yellow film in the mouth; raw feeling in the throat; and pain.

Treatments for Oral Mucositis

Until recently, there were no approved treatments to prevent mouth sores or reduce their severity. However, new research is leading to better ways of treating this side effect.

Current treatment options include the following:

Palifermin (Kepivance) is approved by the U.S. Food and Drug Administration (FDA) for people with blood cancers treated with stem cell transplant and high-dose chemotherapy. These types of patients have a higher chance of developing mouth sores. Doctors call palifermin, a targeted treatment, a promising advance in preventing and healing mouth sores.

“Cold therapy” is a technique that nurses devised for people receiving the chemotherapy 5-FU. Starting five minutes before getting the drug and continuing for about half an hour, patients suck on ice chips. This closes the blood vessels in the mouth so that they are less affected by the drug as it goes through the bloodstream. (The damaging effects of 5-FU tend to drop off after half an hour.) Cold therapy seems to work best for patients who receive a single, large dose of 5-FU rather than smaller doses delivered over time. Studies show that people who use the ice chips have about half the amount of mouth sores and pain as people who do not use the ice chips. The technique has also been used with other types of chemotherapy.

Controlling Mouth Pain

There are a number of medications available to control pain caused by oral mucositis. You can buy some of them over the counter. Others require your doctor’s prescription.

Over-the-counter pain relievers for mild pain include ibuprofen (such as Motrin) and acetaminophen (such as Tylenol).

Over-the-counter local anesthetics such as Xylocaine, Anbesol, or Orajel may also be effective for mild pain. Let your doctor know if you are using them, especially if he or she prescribes a lidocaine-based mouthwash.

Prescription pain medications such as Gelclair, an oral gel, coat and soothe mouth sores by forming a protective barrier in the mouth. Gelclair contains three key ingredients: one substance to coat the raw tissues in the mouth and form a protective film over them; a second substance to moisten the tissues; and licorice root extract, for flavoring.

Another prescription product specifically for use in the mouth is “magic mouthwash.” It contains Maalox to coat the mouth and lidocaine to relieve the pain. Some pharmacies that specialize in cancer care offer their own versions of magic mouthwash.

Opiates, which are stronger prescription drugs for severe pain, should be used if you need them. Pain may cause fatigue, sadness, stress, or worry, and can affect your quality of life. Talk with your doctor about using opiates, a class of drugs that includes morphine, for effective pain relief.

For people who cannot swallow pills because of mouth sores, opiates are also available in liquids and skin patches. The pain-relieving drug seeps into the skin from the patch and enters the bloodstream, where it travels to the mouth.

A fast-acting opiate called fentanyl citrate (Actiq) is available in a berry-flavored lozenge on a stick. Like a cough drop, the lozenge dissolves in the mouth. The drug is delivered quickly into the bloodstream. This medication is intended only for adults who are already taking other opiates.

Patient-controlled analgesia is also an option for some patients. This refers to the use of a portable pump through which a prescription drug, usually an opiate, flows under the skin or into a vein. If more pain relief is needed, a simple push of a button increases the dose temporarily.

Using the Team Approach

Today, many different kinds of health care providers come together as a team to care for people with cancer. If you experience mouth sores, your doctor and nurse are your best resource to help prevent and manage this side effect. But there are other important members of the team you should consult: your dentist, a registered dietitian, and an oncology social worker for help with practical and emotional concerns.

Caring for Your Teeth and Gums

The best time to start managing mouth sores and caring for your mouth is before cancer treatment begins. Your dentist should perform a careful examination to make sure there are no broken teeth, cavities, or gum irritation. If you wear dentures, he or she should check to make sure they fit well. The following are some ways you can care for your mouth before, during, and after treatment:

Keep your mouth clean with careful brushing. Use the softest bristle brush available or an oral sponge. Rinsing the bristles in hot water can make them even softer. If toothpaste irritates your mouth, use a mixture of half a teaspoon of salt with four cups of water.

Floss gently. There is no need to floss more than once a day during your cancer treatment. It’s OK to skip the areas that feel too tender. Talk with your dentist about other ways to keep those areas clean.

Gargle regularly. Use a solution made up of one quart of plain water, half a teaspoon of table salt, and half a teaspoon of baking soda.

Drink plenty of fluids. Aim for two or three quarts a day. Talk with your doctor or dietitian about the types of fluids you should drink.

Fight dry mouth with water or sugarless drinks. If you have dry mouth, it can make mouth sores more painful. Avoid caffeine, tobacco and alcohol, as well as spicy, peppery, or salty foods, which can make dry mouth more severe, especially if you have mouth sores.

Making It Easier to Eat

With mouth sores, you may need to change your diet to make sure you get enough calories and nutrients. A registered dietitian can recommend liquid supplements to help you maintain your weight and make sure you’re getting enough liquids. There are also things you can do:

Choose foods that are soft, moist, and creamy, or blend foods to make them easier to swallow. The blender also makes great milkshakes and smoothies. Sipping blended food with a straw helps avoid areas in the mouth that are tender and sore. You can also eat foods such as cottage cheese, yogurt, mashed potatoes, and avocadoes. Avoid pretzels, crackers, or chips, which could irritate a mouth sore.

Avoid acidic foods and beverages. For example, oranges, grapefruits, lemons, limes, tomatoes and pineapple can further irritate mouth sores.

Make sure that each bite is packed with high calories and protein. To do that, try adding protein in the form of powdered milk or whey protein. Use milk with dry cereal or when cooking oatmeal, scrambled eggs, pudding, or cream soups. Peanut butter, butter, and cream can also add needed calories to foods.

Use supplements. Ensure, Boost, Carnation Instant Breakfast, and similar products can help you meet your nutritional needs. If it’s too painful to swallow solid foods, it’s OK to substitute four to six eight-ounce shakes per day.

Drink liquids with calories. Because fluids and calories are both so important, be sure to drink liquids that give you both, such as milk and non-acidic juice. Non-acidic popsicles are another option.

Treat yourself to some ice cream. Because it is soft, high in calories, and contains lots of protein and fluid, ice cream is a good food to eat when you have mouth sores.

Q. My mouth sores developed after I received radiation to my jaw. I have a lot of mucus build-up in my mouth. How can I deal with this?

A. There are a number of things both you and your doctor can do to control mucus:
* Rinse and gargle often with a salt and baking soda mixture. Stir half a teaspoon of table salt and half a teaspoon of baking soda into a quart of plain water.
* Use a humidifier at night to help thin out the mucus.
* Ask your doctor about cough syrups that contain chlorpheniramine, such as Tussionex or Hycodan. These products can reduce secretions.
* Your doctor may also recommend cough medicines that contain guaifenesin, such as Robitussin DM or Humibid, to thin the mucus.
* If the secretions become very heavy, your doctor may need to order a portable suction machine that you can use to remove the mucus.

Q. My dentist tells me that I need a root canal. Is it okay to have this done during my cancer treatment?

A. In order to make that decision, your dentist needs to consult with your oncologist about the status of your blood counts, including your white blood cells. These cells are important to the immune system for fighting infection. If your white cell count is low, it might be best to delay the root canal and treat any tooth pain or infection with antibiotics and pain medication first. After a few days, when the white blood cells return to a safe level and your oncologist feels it is safe for you to have the root canal, you can have the procedure. But before you go ahead, be sure to discuss it with your cancer care team.

Q. Is there any way to prevent mouth sores after receiving radiation or chemotherapy?

A. When it comes to radiation, newer technologies are helping to spare healthy tissues and reduce damage to the lining of the mouth. And as discussed in this booklet, there are effective ways to manage this side effect and lessen its symptoms. However, at the moment there is no known way to prevent mouth sores completely. That’s why it is important to ask your health care team whether your particular treatment may cause mouth sores and if so, to work closely with the different members of your team to manage them.

Seeing your dentist for screening before starting cancer treatments is especially important. He or she can recommend the type of toothbrush and mouthwashes to use during treatments. Keeping in close touch with your dentist and medical oncologist will enable you stay on top of any mouth sores you may develop.


Charles L. Loprinzi, MD
Regis Professor of Breast Cancer Research, Mayo Clinic, Rochester

Douglas E. Peterson, DMD, PhD
Professor of Oral Medicine and Chair, Program in Head & Neck Cancer and Oral Oncology, Neag Comprehensive Cancer Center, University of Connecticut Health Center

Melinda Bivins, RD, CSO, LD
Clinical Dietitian, The University of Texas MD Anderson Cancer Center

Carolyn Messner, DSW
Director of Education and Training, CancerCare

Glenn Meuche, MSW
Coordinator, CancerCare

Find More Publications

Browse by Diagnosis

Browse by Topic

Thumbnail of the PDF version of Managing Oral Mucositis

Download a PDF (1.69 MB) of this publication.

This e-booklet was made possible by a grant from Allos Therapeutics, Inc.

The information presented in this publication is provided for your general information only. It is not intended as medical advice and should not be relied upon as a substitute for consultations with qualified health professionals who are aware of your specific situation. We encourage you to take information and questions back to your individual health care provider as a way of creating a dialogue and partnership about your cancer and your treatment.