Treatment Side Effects - Mouth Sores

Reviewed by: HU Medical Review Board | Last reviewed: January 2017.

People with lung cancer who receive chemotherapy may experience mouth sores as a side effect of treatment. Mouth sores can range in severity from an inconvenience to becoming a severe complication that may delay or cause treatment to be discontinued.1

What are mouth sores?

Mouth sores are areas of discomfort or ulcers in the mouth that may form on the lining of the mouth, in the esophagus (connecting the throat to the stomach), or on the lips. These sores can cause pain and distress, making it difficult to speak, eat, swallow or breathe.

In addition to mouth sores, patients may experience painful gums, dry mouth, swelling or peeling of the tongue, infection, or change in taste.1,2

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Why do mouth sores occur from chemotherapy?

Chemotherapy targets rapidly dividing cells, such as cancer cells. However, because chemotherapy drugs attack all cells that are dividing quickly, the treatment affects cancer cells as well as normal cells that divide quickly, such as cells in the bone marrow, the lining of the intestines, hair follicles, and the cells in the lining of the mouth. Side effects from chemotherapy can include problems with teeth, gums, the lining of the mouth, and the glands that make saliva.2

Managing mouth sores

Prior to beginning chemotherapy, patients should visit their dentist to take care of any existing problems and professionally clean their teeth. Once treatment with chemotherapy begins, patients should maintain proper dental hygiene and check their mouth for any sores. Dental hygiene practices can be modified when experiencing mouth sores:2

  • Use a soft toothbrush
  • Avoid mouthwashes with alcohol in the ingredients
  • Gently floss every day, avoiding areas that are sore or bleeding
  • Rinse the mouth several times a day with a solution of ¼ teaspoon of salt or 1 teaspoon of baking soda in 1 cup of warm water, followed by a plain water rinse

Lessen or ease mouth sores

There are several techniques that can lessen or ease mouth sores, including:2,3

  • Stay hydrated and drink lots of water
  • Suck on ice chips
  • Use sugarless gum or sugar-free hard candy
  • Use a saliva substitute to moisten the mouth
  • Choose foods that are easy to chew and swallow
  • Take small bites of food and chew slowly
  • Sip liquids with meals
  • Soften foods with gravy, sauces, broth, or other liquids
  • Avoid sharp or crunchy foods that may cut the mouth
  • Avoid spicy foods or foods high in acid, like citrus fruits and juices
  • Avoid toothpicks
  • Eliminate any tobacco products
  • Avoid alcoholic drinks
  • Frequently use lip moisturizer

Medications to help manage side effects

Over-the-counter medications that can help ease pain include topical agents like Orajel™ or Zilactin®-B. A solution can be made to swish around the mouth using equal parts of viscous lidocaine, Zovirax® and Maalox® or Mylanta®. This solution can be swished around the mouth and spit out every 2-4 hours as needed. This is one example of a solution that can be used, but such solutions can vary and contain different ingredients depending on what a patient’s doctor prescribes. For severe pain, oral pain medications may be prescribed.3