A canker sore is a small, shallow sore that develops on the soft tissues in your mouth or on your gums. They’re usually white or yellow and may have a red border. Canker sores can make eating and talking uncomfortable. But they’re not contagious like cold sores.

Canker sores are common. Most people get them at some point in their lives. They’re more common in women than men and usually happen between the ages of 10 and 20. But you can get them at any age.

Types of Canker:

There are two types of canker sores:

1. Minor Canker Sores measure less than 1 centimeter (0.4 inches) across. They’re the most common type and usually heal within a week or two without treatment.

2. Major Canker Sores measure more than 1 centimeter (0.4 inches) across and take longer to heal. You may get one or more of these sores at a time.

What causes Canker Sores?

The exact cause of canker sores isn’t known. But there are some things that may trigger them, such as:

  • A minor injury to your mouth from dental work, brushing your teeth, or wearing braces
  • Hormonal changes during your menstrual period
  • A weakened immune system
  • Stress
  • Foods, such as chocolate, coffee, strawberries, and nuts
  • A bacterial or viral infection

What are the symptoms of a Canker Sore?

1. The main symptom of a canker sore is a small ulcer (open sore) on your tongue, inside your cheek, or on the back of your throat. You may notice a tingling or burning feeling a day or two before the sore appears.

2. The sore is usually round and white or yellow in the center with a red border. It’s usually about 1 to 3 millimeters (mm) across. You may have just one canker sore or a cluster of several sores.

3. Canker sores usually go away on their own in 7 to 10 days. But they can be painful, especially when you eat or drink.

How are Canker Sores diagnosed?

Your doctor can usually diagnose a canker sore just by looking at it. He or she may also ask about your medical history and whether you have any other symptoms.

If your doctor thinks you have a more serious condition, such as an infection, he or she may do a physical exam. He or she may also order tests, such as a blood test or a culture of the sore. A culture can help find out if you have a bacterial or viral infection.

How are Canker Sores treated?

Most canker sores go away on their own in 7 to 10 days. But there are things you can do to ease the pain and speed up healing.

  • Rinse your mouth with warm salt water several times a day.
  • Place a cold, wet cloth on the sore.
  • Put a numbing gel or cream on the sore. You can buy these without a prescription at the drugstore.
  • Apply a topical ointment that contains zinc oxide, such as Orabase, to the sore. You can buy this without a prescription.
  • Take over-the-counter pain relievers, such as ibuprofen (Advil, Motrin IB) or acetaminophen (Tylenol), to help relieve pain.


If you have a canker sore, there are things you can do to ease the pain and speed up healing. Most canker sores go away on their own in 7 to 10 days. But if yours doesn’t go away after a couple of weeks, is very painful, or is making it hard to eat or drink, see your doctor. He or she may prescribe a stronger pain reliever or a mouthwash that contains a numbing agent or an antibiotic.