Currently there is no known cure for canker sores. However, there are treatments which can help ease the pain and discomfort and help them heal.

The type of treatment depends in part on the severity of the sore.

Minor canker sores can be treated with home remedies or over-the-counter products.
Some of the home remedies include bathing the area with a salt water and sodium bicarbonate solution and swabbing with a solution of water and hydrogen peroxide.

Saltwater and Sodium Bicarbonate:
Mix ½ tsp sale with ½ cup warm water. Swish this solution around in your mouth and then spit (preferably in the sink). You can also add baking soda to the mix and make a paste. Cover the canker sore with this paste and it should take some of the pain away.

Hydrogen Peroxide Remedy
Mix even amounts of hydrogen peroxide and warm water. With a cotton swap gently dab the solution onto the canker sore. Do not swallow the solution.
Major canker sores such as those that do not go away or have developed secondary infections must be treated by your dentist. These treatments can include prescription antibiotics or steroids. Canker sores is a problem you dentist has seen many times and he or she will be able to help.