Understanding Cancer Treatment and Mouth Sores

Aug 15, 2023


This cancer treatment side effect can be painful, but at-home remedies can help.

Cancer treatment wreaks havoc on the body. Side effects of chemotherapy and radiation can include hair loss, extreme fatigue, nausea and loss of appetite. This treatment can also cause several issues in the mouth and throat. One lesser-known but common side effect is oral mucositis, also known as "chemo mouth."

What is oral mucositis anyway?

Radiation and chemotherapy are excellent at targeting and killing cancer cells. They can also damage noncancerous cells in the process. When cellular damage occurs in the oral mucosa, the protective mucous layer that covers soft tissues in the mouth, the mucosa is incapable of healing, which leads to the development of chemo mouth. People who have chemo mouth experience inflammation and irritation of the gums, tongue and inner cheeks that can develop into ulcers. Some people also lose their sense of taste or have a metallic taste in their mouth.

The sores caused by chemotherapy can be extremely painful, making it difficult to eat or drink comfortably. If untreated, chemo mouth can lead to bleeding in the mouth, trouble eating or swallowing, and infection. In severe cases, people who can’t eat or drink without pain may need to get nutrients through a feeding tube.

Mouth sores typically develop within five to 14 days of starting chemotherapy or after three weeks of receiving radiation therapy to the head or neck.

During cancer treatment, some people will also experience a mouth condition called oral thrush, which can also be painful. This is a different condition than oral mucositis, so it is important to share your symptoms with your oncology provider so you can be assessed and your provider can recommend the best options for treatment.

Who usually gets these mouth sores?

Chemo mouth is a common side effect of chemotherapy, as well as radiation to the head and neck, which can be used to treat cancer of the throat, tongue, tonsils and larynx. People undergoing treatment for all cancers, including breast, lung, colorectal and prostate, can experience chemo mouth. In fact, up to 40% of people receiving chemotherapy for solid tumors develop it. The chance is even higher for people who have bone marrow transplants or higher-than-normal doses of chemotherapy, with a 76% risk.

This oral condition is more common in younger people, as well as those with poor nutrition or oral care. See your dentist before starting cancer treatment to address any outstanding oral issues, including gum disease and cavities. Ask your cancer care team for advice on what to eat to support your immune system during treatment, which can reduce your chance of developing mouth sores from chemo or radiation.

Is chemo mouth preventable?

During cancer treatment, take these steps to reduce your chance of developing chemo mouth:

  • Rinse your mouth with salt water or alcohol-free mouthwash after every meal and before bed if advised by your oncologist or another provider.
  • Use a clean, dry, soft-bristle toothbrush and replace it often.
  • Don’t use toothpaste, mouthwash or other oral treatments with tooth whiteners, which can cause inflammation.

How can I get rid of mouth sores naturally?

Try these at-home remedies to treat mouth sores from chemotherapy or radiation naturally:

  • Increase your toothbrushing frequency. Use a clean, soft-bristle toothbrush and replace it often. See your dentist for ongoing care during treatment.
  • Rinse your mouth with salt water or a baking soda mouthwash every four hours to reduce inflammation.
  • Drink plenty of water.
  • Avoid tobacco and alcohol, which can irritate your mouth.
  • Don’t eat sharp, hard, spicy or acidic foods, such as tomatoes or citrus, which can irritate or injure the mouth.
  • Take zinc supplements, which may improve tissue repair.

If you still have mouth sores or your pain doesn’t subside, talk to your care team about other treatment options. Your provider may prescribe a topical pain reliever, medicated mouthwash or other treatment options for chemo mouth.