Mucositis is inflammation of the mucosa, the mucous membranes that line your mouth and your entire gastrointestinal tract. It’s a common side effect of cancer treatments involving radiation or chemotherapy. Mucositis is temporary and heals on its own, but it can be painful and carries certain risks. It requires self-care and medical care to manage.


What is mucositis?

Mucositis is a painful inflammation of the mucosa — the protective mucous membrane that lines your entire gastrointestinal (GI) tract, from your mouth through your intestines. Mucous membranes line many cavities and canals in your body, but mucositis particularly affects those in your digestive system, especially your oral mucosa. It’s a common side effect of certain cancer treatments, including chemotherapy, radiation therapy, or stem cell transplants (bone marrow transplants).

How does mucositis affect my body?

Therapies designed to treat cancer will attack any cells that rapidly divide. Unfortunately, that includes any mucosa in the area — these therapies can’t discriminate between the two. Mucous membranes line your entire GI tract, including your mouth, throat, esophagus, stomach and small and large intestines.

Ordinarily, rapid cell turnover is part of what makes your mucosa the protective barrier that it is. It allows the mucous membrane to regularly refresh itself, clearing out abrasive particles and pathogens and healing quickly from injuries.

Mucositis not only damages the existing cells in your mucosa, but also their ability to replicate themselves and heal. This means that parts of your body that normally require that protective barrier are now exposed to irritation from their everyday functions. In your digestive system, that’s eating. These parts are also more vulnerable to infection.

Mucositis most commonly affects your mouth and the inner lining of your cheeks (buccal mucosa). These mucous membranes are particularly sensitive. Oral mucositis makes the inside of your mouth inflamed — red, shiny, swollen, raw and painful. It often leads to mouth sores or white patches of pus in your mouth.

Oral mucositis can be mild or severe. Healthcare providers have a grading system for pain levels, with grades 1 and 2 being relatively mild and grades 3 and 4 being severe. Severe cases can interfere with eating and can cause people with cancer to reduce their treatment.

Some people also get gastrointestinal mucositis. This may manifest as abdominal pain and nausea if the inflammation is closer to your stomach, or as diarrhea or painful bowel movements if the inflammation is in your colon.

Who does mucositis affect?

Up to 50% of people receiving chemotherapy and 80% to 100% of people receiving local or whole-body radiation therapy or stem cell transplants (bone marrow transplants) develop mucositis.

You may be more likely to be affected or have more severe mucositis if you:


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Symptoms and Causes

What are the signs and symptoms of mucositis?

Inflammation causes redness, soreness, heat and swelling. It can cause other specific symptoms in different parts of your body.

Oral mucositis may cause:

Gastrointestinal mucositis may cause:

What causes mucositis?

When healthcare providers talk about mucositis as a condition, they’re usually talking about mucositis of the GI tract (including the mouth) that results from cancer treatments. These treatments damage rapidly dividing cells, including those that make up the mucosa. High-dose radiation or chemotherapy to the whole body, or low-dose treatments to the local area, may affect your mouth or abdominal organs.

Inflammation of the mucosa can also occur in conjunction with other conditions, such as infection. But when this happens, it usually goes by a more specific name. For example, stomatitis is inflammation of the mouth, and gingivostomatitis is inflammation of the mouth that’s caused by infection.


What are the complications of mucositis?

  • Undernutrition. Pain in your mouth, throat, esophagus or digestive organs can make it hard to eat. This can have serious consequences for people with cancer, who are already prone to food aversion and weight loss, and for whom adequate nutrition is especially important. As many as 70% may require hospitalization for tube feeding.
  • Chronic diarrhea. People with persistent diarrhea or blood in their poop may have to be hospitalized and monitored to protect against dehydration or anemia from blood loss.
  • Infection. When mucous membranes are broken down, your body loses one of its most important protective barriers against infection. People who have cancer already tend to have low white blood cell counts, which reduces their immunity. Mucositis can also produce open sores, inviting infection of your bloodstream. People receiving chemotherapy with mucositis and neutropenia (white blood cell deficiency) are at special risk of septicemia, a systemic infection of their bloodstream.
  • Reduction of cancer treatment. Severe mucositis may require some people with cancer to postpone or reduce their treatment, which poses additional risks to their health. More than 30% of people discontinue treatment as a result of the condition.

Diagnosis and Tests

How is mucositis diagnosed?

Mucositis is an expected side effect of cancer treatment and is easy to diagnose based on your symptoms, medical history and a look at the inflamed tissues. In the case of gastrointestinal mucositis, it may take an imaging test to see the tissues inside. Your healthcare provider may also want to test you for certain bacterial or fungal infections. They can do this with a simple blood test.


Management and Treatment

How is mucositis treated?

Mucositis will heal on its own after your course of cancer treatment has finished. If you have chemotherapy, mucositis usually appears one to two weeks after beginning treatment and heals after one to six weeks. If you have radiation therapy, mucositis appears two to three weeks after beginning treatment and heals within two to four weeks after your therapy has finished. How severe it is, and how well you take care of it to prevent additional irritation, can affect how long it takes to heal. While it’s healing, you’ll require:

Pain management

Pain is a serious problem with mucositis, especially in the mouth. Topical agents may not last long in your mouth, or may not be able to reach all the affected areas. You may need a combination of different approaches to manage your pain, including topical gels and mouthwashes, over-the-counter pain medications and even prescription opioids. Don’t try to tough it out — it’s important that you’re able to eat and drink well enough to continue healing. Talk to your healthcare provider about pain management in cancer care.

Pain treatments for mucositis include:

Mouth care

When you have oral mucositis, you have to take special care of your mouth, not only to reduce discomfort, but also to protect it from additional irritation and infection. Even normal things like chewing, speaking and swallowing can contribute to breaking down your weakened mucosa. This means choosing gentle foods and products to help lubricate and coat your mouth and throat. Your weakened mucosa is especially vulnerable to infection, so hygiene is extra important, too.

Oral mucositis care includes:

  • Extra — but gentle — brushing. Three to four times a day is recommended. Make sure to use soft bristles and a gentle fluoride toothpaste. Don’t use whitening agents. If toothpaste irritates your mouth, use a salt and baking soda paste. Floss gently. Clean dentures daily.
  • Mouth rinsing. Rinse your mouth five or six times a day with salt water or a salt and baking soda solution. This is one of the gentlest and most effective ways of cleaning and sanitizing mouth sores. You can also use alcohol-free antiseptic mouthwashes.
  • Diet. Your diet should be soft and mild. Avoid acidic, spicy and crunchy foods. Avoid sugar and alcohol, which are abrasive and encourage bacterial and fungal overgrowth. Protein shakes are a good idea to boost your nutrition and hydration.
  • Hydration. You’ll need to drink extra fluids to compensate for your dry mouth and the loss of lubrication in your GI tract. You may want to try an artificial saliva such as enzyme-based Oral Balance®. Some people find that sucking on ice chips provides lubrication and a pleasant numbing effect. You should also protect your lips with balms.

Treating complications

If you develop severe dehydration, undernutrition or infection, you may require:

What should I eat or drink while healing from mucositis?

Do eat:

  • High protein foods.
  • Nutritional shakes.
  • Soft foods.
  • Sugar-free popsicles.

Don’t eat:

  • Spicy foods.
  • Acidic foods.
  • Greasy or fried foods.
  • High-sugar foods.

Do drink:

  • Chamomile tea.
  • Lots of water.

Don’t drink:

  • Carbonated beverages.
  • Alcohol.


Can mucositis be prevented?

There’s not much in our toolbox yet to prevent mucositis from cancer treatment, but healthcare providers are working on it. Several medications are being tested that may help reduce the length and severity of the condition for certain people. Options include:

  • Cryotherapy. Sucking on ice chips before and during chemotherapy treatments can help protect against oral mucositis.
  • Palifermin. This drug is a synthetic version of keratinocyte growth factor (KGF), a substance your body produces to help protect and repair the cells that line your mouth and GI tract. It’s been shown to reduce the length and severity of mucositis in people with blood cancer undergoing bone marrow or stem cell transplants.
  • Topical agents. Two topical gels, Gelclair® and Zilactin®, have been shown to reduce oral mucositis by coating and protecting the mucosa before radiation treatments.
  • Amifostine. This drug may lessen the severity of oral mucositis in people receiving radiation therapy to their head and neck when taken in advance. It may cause nausea as a side effect.

Outlook / Prognosis

What can I expect if I have this condition?

It will heal on its own after your cancer treatment has finished, but it may take two to six weeks. You may need prescription pain medication to get through it. You can help it heal faster by taking special care of your mouth and practicing careful hygiene to avoid infection. If you do get an infection, or if you’re having trouble eating and drinking, seek medical care.

Living With

When should I see my healthcare provider?

Seek medical care when you notice:

  • The first signs of mucositis.
  • Any signs of infection, such as fever.
  • You’re having trouble eating or drinking.
  • You’re losing weight.
  • You have chronic diarrhea.
  • You have persistent bleeding in your mouth or poop.

A note from Cleveland Clinic

Mucositis is one of the most predictable and difficult side effects of cancer treatment. How severe it is will depend on many factors, including your overall health, the type of treatment you’re receiving and how well you take care of yourself after treatment. Some of these factors can’t be prevented, but you can help prepare and protect yourself by following basic health guidelines: avoiding smoking and alcohol and practicing good oral hygiene and nutrition.

If you do have severe mucositis, make sure to keep your healthcare provider informed of your condition and ask for the help you need. Mucositis is temporary, but it’s not worth suffering through when you can help it. These brief weeks following your cancer treatment are crucial to your good recovery, and the risks of undernutrition or infection during this period are real. Self-care and medical care are equally important when you have mucositis.

Medically Reviewed

Last reviewed on 07/24/2022.

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