Oral Ulcers

Oral ulcers are painful, shallow sores around the lining of the mouth. They can affect the gums, the inside of the lips and the cheeks (sores on the outside of the lips and on the face are different). They typically first occur in school aged children and teenagers. Oral ulcers may also be called canker sores or cold sores.


Canker sores and cold sores can be caused by many factors including:

  • Infection.

  • Injury.

  • Sun exposure.

  • Medications.

  • Emotional stress.

  • Food allergies.

  • Vitamin deficiencies.

  • Toothpastes containing sodium lauryl sulfate.

The Herpes Virus can be the cause of mouth ulcers. The first infection can be severe and cause 10 or more ulcers on the gums, tongue and lips with fever and difficulty in swallowing. This infection usually occurs between the ages of 1 and 3 years.


The typical sore is about ¼ inch (6 mm) in size, is an oval or round ulcer with red borders.


Your caregiver can diagnose simple oral ulcers by examination. Additional testing is usually not required.


Treatment is aimed at pain relief. Generally, oral ulcers resolve by themselves within 1 to 2 weeks without medication and are not contagious unless caused by Herpes (and other viruses). Antibiotics are not effective with mouth sores. Avoid direct contact with others until the ulcer is completely healed. See your caregiver for follow-up care as recommended. Also:

  • Offer a soft diet.

  • Encourage plenty of fluids to prevent dehydration. Popsicles and milk shakes can be helpful.

  • Avoid acidic and salty foods and drinks such as orange juice.

  • Infants and young children will often refuse to drink because of pain. Using a teaspoon, cup or syringe to give small amounts of fluids frequently can help prevent dehydration.

  • Cold compresses on the face may help reduce pain.

  • Pain medication can help control soreness.

  • A solution of diphenhydramine mixed with a liquid antacid can be useful to decrease the soreness of ulcers. Consult a caregiver for the dosing.

  • Liquids or ointments with a numbing ingredient may be helpful when used as recommended.

  • Older children and teenagers can rinse their mouth with a salt-water mixture (1/2 teaspoonof salt in 8 ounces of water) four times a day. This treatment is uncomfortable but may reduce the time the ulcers are present.

  • There are many over the counter throat lozenges and medications available for oral ulcers. There effectiveness has not been studied.

  • Consult your medical caregiver prior to using homeopathic treatments for oral ulcers.


  • You think your child needs to be seen.

  • The pain worsens and you cannot control it.

  • There are 4 or more ulcers.

  • The lips and gums begin to bleed and crust.

  • A single mouth ulcer is near a tooth that is causing a toothache or pain.

  • Your child has a fever, swollen face, or swollen glands.

  • The ulcers began after starting a medication.

  • Mouth ulcers keep re-occurring or last more than 2 weeks.

  • You think your child is not taking adequate fluids.


  • Your child has a high fever.

  • Your child is unable to swallow or becomes dehydrated.

  • Your child looks or acts very ill.

  • An ulcer caused by a chemical your child accidentally put in their mouth.