Mouth Sores or Mucositis

Approved by the Cancer.Net Editorial Board, 11/2018

A person with cancer may have swelling inside the mouth and throat that can lead to painful mouth sores. This condition is also called mucositis.

Talk with your health care team if you have pain or other changes in your mouth during cancer treatment. Relieving side effects is an important part of cancer care and treatment. This is called palliative care or supportive care.

Causes of mouth sores

Understanding the cause of your mouth sores will help you better manage it with your health care team. Several things can cause mouth sores related to cancer and cancer treatment:

  • Chemotherapy. Up to 40% of people receiving chemotherapy have mouth sores.

  • Radiation therapy to the head and neck area.

  • Bone marrow/stem cell transplant. Mouth sores are a possible sign of graft-versus-host disease, which is a side effect of these procedures.

Managing mouth sores

The best way to manage mouth sores is to prevent them or treat them early. Here are some ways to prevent and treat mouth sores:

  • Suck on ice chips right before and during each chemotherapy treatment. This may prevent mouth sores caused by certain types of chemotherapy.

  • Your doctor may recommend these pain-relief strategies if you develop mouth sores:

    • A mouthwash solution that contains lidocaine. It is sometimes called magic mud, magic mouthwash, or triple mix

    • Over-the-counter drugs, such as acetaminophen (Tylenol). But, it is important to avoid taking aspirin during cancer treatment unless your doctor tells you otherwise.

    • Prescription pain medicine

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

  • Visit an oral oncologist before starting radiation therapy to the head and neck. An oral oncologist is skilled in managing dental health for people with head and neck cancer.

  • Brush your teeth gently with fluoride toothpaste several times a day. If the mouth sores are severe, use a toothette instead of a toothbrush. A toothette is a sponge on a stick.

  • Floss gently.

  • Rinse or gargle with a solution of saltwater and baking soda. Try a solution of 1/2 teaspoon of salt plus 1/2 teaspoon of baking soda in a glass of water. Avoid mouth rinses that have alcohol in them.

  • Lessen the time that you wear your dentures. Avoid wearing them at night. Consider removing them between meals to help reduce mouth irritation.

  • Choose foods that require little or no chewing.

  • Avoid acidic, spicy, salty, coarse, and dry foods.

Related Resources

Side Effects of Chemotherapy

Side Effects of Radiation Therapy

More Information

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