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Canker Sore Causes, Relief, and Prevention

Canker Sore Causes, Relief, and Prevention

May 21, 2018

Ow. Yeah. Canker sores. Not pleasant to talk or think about, but they happen. So, what can you do?

Here’s what they are, why we get them, and how to deal with them.

What's a Canker Sore?

Canker sores are among the most common of oral conditions and are experienced by more than half of the population. They’re small, painful, yellowish, shallow lesions that develop on the soft tissues (lips, cheeks) in your mouth or at the base of your gums. Many people experience a tingling or burning sensation a day or two before a canker sore appears.

Canker sores are not the same thing as cold sores. Cold sores are caused by the herpes simplex virus and appear on the outside of your mouth and lips. Cold sores are blisters that break, ooze, and turn into a yellowish crust or scab that eventually falls off.

Causes of Canker Sores


Canker sores can be caused by a variety of things. The most common causes include:

  • Viruses
  • Bacterial infections
  • Food allergies
  • Poor nutrition
  • A weakened immune system
  • An injury or trauma to the mouth
  • Lack of sleep
  • Hereditary factors (family history)

Many studies have also shown that people tend to have outbreaks when they experience stress, which can do a number on your immune system.

How to Treat and Relieve Canker Sores


Most of the time, you won’t have to do anything. Pain from mild canker sores typically goes away in a couple of days, and the sores will clear up in about two weeks. 

Major canker sores, however, are extremely painful, and can take up to six weeks to clear up.

Here are some remedies you can try the next time you experience the pain and discomfort of a canker sore:

  • Mouth Rinses. You have to visit your doctor or dentist for this one. They can prescribe a mouth rinse containing the steroid dexamethasone to reduce pain and inflammation, or lidocaine to reduce pain.
  • Topical Products. Your local drugstore carries a variety of over-the-counter products – pastes, creams, gels, liquids – which may help relieve pain and speed the healing process if applied as soon as sores appear.
  • Cautery of Sores. This is performed by a medical or dental professional and only used in sever canker sore cases. Your doctor or dentist can use an instrument or chemical substance to cauterize (burn) the canker sore to prevent further damage or infection.
    • Debacteral can reduce healing time to about a week.
    • Silver nitrate can relieve the pain, though it hasn’t been shown to speed the healing.
  • Nutrition. Canker sores have been linked to not consuming enough folic acid, vitamin B-6, vitamin B-12, or zinc. So, try eating foods high in these nutrients like fortified oatmeal and cereals.

If your canker sores don’t heal within a couple of weeks or get worse, visit your dentist. They’ll help identify and treat the cause of your canker sores.

How to Prevent Canker Sores


Follow these tips to help keep canker sores at bay:

  • Watch what you eat. Certain foods irritate the soft tissues in our mouths. These foods include anything acidic, salty or spicy. Examples of highly acidic foods include pineapple, grapefruit, and oranges. For the spicy foods, try not to eat too many jalapenos or salsa.  Also, be sure to avoid any foods to which you’re sensitive or allergic.
  • Eat healthy foods. Eat plenty of fruits, veggies, and whole grains for proper nutrition.
  • Practice good dental hygiene. Brush and floss regularly to keep your mouth clean and free of foods that might trigger a sore. Use soft bristles, and avoid toothpastes and mouth rinses that contain sodium lauryl sulfate.
  • Protect your mouth. If you have braces or other dental appliances, ask your dentist about orthodontic waxes to cover the sharp edges.
  • Reduce stress. If you have stress-induced canker sores, look into stress-reduction techniques, such as meditation and guided imagery.

Want to learn more?


If you have any questions, talk to your dentist. They’ll help you understand the causes for your canker sores and help treat them.

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