Springdale Mason Pediatrics

Canker Sores


  • Painful, shallow ulcers (sores) on the inner lips or cheeks
  • Not caused by an infection

Call or Return If

  • Mouth ulcers last more than 2 weeks
  • You think your child needs to be seen
  • Your child becomes worse

About This Topic


  • Small ulcers have a white center with a red border around them
  • Size is usually less than ΒΌ inch (6 mm)
  • Found on the inner lips and inner cheeks
  • The sores are very painful, even when not eating
  • Usually get 1 canker sore at a time. Sometimes get 2 or 3.
  • No fever or other symptoms


  • Canker sores have many causes. Often, the cause is unknown.
  • Minor injuries to the mouth can trigger a canker sore.
  • Examples are from a rough food or a hard toothbrush. Biting oneself while chewing can start one.
  • Food allergies or irritants may also be a trigger.
  • More common during menstrual periods
  • Vitamin deficiencies can also be a cause. A vitamin deficiency can occur if your child is a picky eater.
  • Canker sores can run in families (genetic).
  • Not caused by the Herpes virus or other infections

After Care Advice

  • Canker sores are the most common cause of unexplained mouth ulcers.
  • They happen in healthy children.
  • They are harmless and go away on their own.
  • Here is some care advice that should help.
Liquid Antacid for Mouth Pain:
  • For mouth pain, use a liquid antacid such as Mylanta or the store brand. Give 4 times per day as needed. After meals often is a good time. Age: Can use for children over 1 year old.
  • For children over age 6, can use 1 teaspoon (5 ml) as a mouth wash. Keep it on the ulcers as long as possible. Then can spit it out or swallow it.
  • For younger children age 1 to 6, put a few drops in the mouth. Can also put it on with a cotton swab.
  • Can use honey instead until you can buy a liquid antacid. Follow the same directions as given for antacids. Avoid honey if less than 1 year old.
  • Caution: Do not use regular mouth washes, because they sting.
Pain Medicine:
  • To help with the pain, give acetaminophen (such as Tylenol) or ibuprofen. Use as needed.
Fluids and Soft Diet:
  • Try to get your child to drink adequate fluids.
  • Goal: keep your child well hydrated.
  • Cold drinks, milk shakes, popsicles, slushes, and sherbet are good choices.
  • Solids. Offer a soft diet. Also avoid foods that need much chewing. Avoid citrus, salty, or spicy foods. Note: Fluid intake is more important than eating any solids.
  • If your child is a picky eater, start your child on a multi-vitamin. Give daily.
Prevention of Recurrent Canker Sores:
  • Avoid minor injuries to the inside of the mouth.
  • Avoid any foods that you think are a cause.
  • Fix any dental problems that are present.
What to Expect:
  • Canker sores heal up in 1 to 2 weeks on their own.
  • Once they start, no treatment can shorten the illness.
  • Treatment can help with the pain.
  • Some children get recurrent canker sores.
Return to School:
  • Children with canker sores do not need to miss any school.
  • Canker sores cannot be spread to others.

Author: Barton Schmitt MD, FAAP
Copyright 2000-2021 Schmitt Pediatric Guidelines LLC
Disclaimer: This health information is for educational purposes only. You the reader assume full responsibility for how you choose to use it.
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