This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science
This page was updated on April 29, 2022.
Mucositis—a condition in which the mouth and digestive system lining become swollen and irritated—is a possible complication of cancer treatment.
Mucositis may be painful. It may also affect your eating habits. But it may be managed. If you develop mucositis as a side effect of treatment, ask your cancer care team how to manage any oral symptoms.
The cells found in the lining of the mouth are fast-growing. Chemotherapy and radiation therapy may inadvertently slow down or even stop these healthy, fast-growing cells from growing normally, thus stopping your mouth tissue from healing at its usual pace.
Both chemotherapy and radiation therapy may also interfere with the balance of healthy bacteria that are normally present in your mouth. In addition, radiation therapy may cause damage to tissue in the mouth and salivary glands, which produce saliva.
Mucositis manifests itself in a number of ways. Possible symptoms include:
Certain factors increase the risk of developing mucositis while you receive treatment for cancer, such as:
Be sure to include a dentist in your cancer care team, especially one who is experienced in treating oral complications caused by cancer treatments. Your dentist may perform a comprehensive examination of your oral health, especially before you start cancer treatment. Your dentist may assess you for:
If you’re receiving certain kinds of treatments, such as chemotherapy, radiation therapy or stem cell transplant, at high doses, it’s important to form an oral care plan with your dentist in order to reduce the risk of oral complications like mucositis.
Furthermore, if you have head or neck cancer and you smoke, you’ll need to stop smoking in order to lower the risk of oral complications.
Inform your cancer care team if you’re experiencing any of the symptoms of mucositis, because in addition to causing you pain, this side effect may impede your ability to speak, eat and drink if it becomes severe—possibly leading to malnourishment and dehydration. Your care team dietitian may be particularly helpful in offering evidence-based advice.
If you have mouth sores as a result of mucositis that make eating and drinking painful, some helpful strategies include:
If you develop a severe case of mucositis, your cancer care team may need to provide you with feeding tubes in order to make sure you stay nourished and hydrated.
It’s important to properly care for your mouth while you’re receiving treatment for cancer, because improper care may increase the bacteria in your mouth. Having too much bacteria in your mouth may lead to an oral infection, which may spread throughout your body.
When caring for your mouth, be sure to: