Mouth Sores or Mucositis

This section has been reviewed and approved by the Cancer.Net Editorial Board, 06/2012

Mucositis is inflammation inside the mouth and throat that can lead to painful ulcers and mouth sores. It occurs in up to 40% of people receiving chemotherapy. In addition to chemotherapy, radiation therapy to the head and neck area may cause mucositis. In people who have received a bone marrow/stem cell transplant, mucositis is a possible sign of bone marrow/stem cell transplant graft-versus-host disease, which occurs when the donated blood cells recognize the patient's body as foreign and attack it.

Relieving side effects, also called symptom management, palliative care, or supportive care, is an important part of cancer care and treatment. Talk with your health care team about any mucositis symptoms you may experience, including any new symptoms or a change in symptoms.

Managing mucositis

The best way to manage mucositis is to prevent it before it starts or to treat it early. Sucking on ice chips immediately before and during each chemotherapy treatment may prevent mucositis caused by certain types of chemotherapy, such as fluorouracil (5-FU, Adrucil) injections. If mucositis occurs, your doctor may recommend a local anesthetic, such as a mouthwash solution that contains lidocaine (sometimes called magic mud, magic mouthwash, or triple mix) or analgesics (drugs, such as acetaminophen [Tylenol], or prescription pain medication). Unless your doctor tells you otherwise, it is important to avoid taking aspirin during cancer treatment. Other drugs to prevent and treat mucositis are currently under investigation.

It is also wise to take special care of your mouth during cancer treatment. The following suggestions may help:

  • Brush your teeth gently with fluoride toothpaste several times a day. Sometimes if the mucositis is severe, a toothette can be used instead of a toothbrush. A toothette is essentially a sponge on a stick.
  • Floss gently.
  • Rinse or gargle with a solution of saltwater and baking soda (1/2 teaspoon of salt plus 1/2 teaspoon of baking soda in a glass of water), and avoid mouth rinses that have alcohol in them.
  • Minimize the time that you wear your dentures. Avoid wearing them at night, and consider removing them between meals to help minimize irritation.
  • Choose foods that require little or no chewing.
  • Avoid acidic, spicy, salty, coarse, and dry foods.

People receiving radiation therapy to the head and neck should see an oncologic dentist (a dentist with experience treating people with head and neck cancer) before beginning treatment. Because radiation therapy can cause tooth decay, damaged teeth may need to be removed. Often, tooth decay can be prevented with proper treatment from a dentist before beginning radiation therapy. Learn more about dental and oral health during cancer treatment.

More Information

Side Effects of Chemotherapy

Side Effects of Radiation Therapy

Managing Side Effects

Additional Resources

National Cancer Institute: Oral Complications of Chemotherapy and Head/Neck Radiation