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Canker Sores

Brief Version

What are canker sores?

Canker sores are painful, shallow sores in the lining of the mouth. They are usually on the inside of lips, inside of cheeks, and gums. They do not cause fever.

The exact cause of canker sores is unknown. Some may result from food that gets stuck in the teeth. Others may be due to forgotten injuries from toothbrushes, toothpicks, rough foods (such as corn chips), hot foods, or biting of the lips or cheeks. Herpes simplex causes fever blisters on the outer lip that come and go but does not cause canker sores on the inside of the mouth.

How can I take care of my child?

  • Pain relief.

    To reduce the pain, your child can swish 1 teaspoon of liquid antacid in his or her mouth for several minutes. For very young children, put a half teaspoon of a liquid antacid directly on canker sores after meals. A child over age 4 with just one ulcer can put an antacid tablet on the sore and let it dissolve. Do this three or four times a day. Give acetaminophen (Tylenol) or ibuprofen (Advil) as needed for pain (especially at bedtime).

  • Diet.

    Offer a soft, bland diet to reduce the pain. Cold drinks and milkshakes are especially good. Avoid giving your child salty foods, citrus fruits, and foods that need much chewing. Encourage your child to drink favorite fluids to prevent dehydration. For very young children, give fluids by cup rather than from a bottle because the nipple can increase the pain.

Call your child's doctor during office hours if:

  • The pain becomes severe.
  • Your child can't drink enough fluids.
  • The sores last longer than 2 weeks.
  • You feel your child is getting worse.
Written by B.D. Schmitt, M.D., author of "Your Child's Health," Bantam Books.
Published by McKesson Provider Technologies.
Last modified: 2006-02-23
Last reviewed: 2006-02-23
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright 2006 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.
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