Ask the experts
Canker sores (also called aphthous ulcers) are shallow, red or white sores that develop anywhere inside the mouth. It is not known exactly why these sores develop, but stress does seem to precipitate canker sores in many people.
Canker sores go away on their own without any treatment; however, doctors often recommend pain relievers such as ibuprofen or acetaminophen if the sores cause significant pain. There are other medications which can be applied directly to the sore to help prevent the sores from becoming further irritated and to help control pain. Many of these are the same type of medications used for teething pain in young children and babies. Examples include Anbesol, Oragel, and Orabase. In severe cases, doctors may recommend prescription medications in the form of tablets or mouthwashes to help relieve pain and inflammation.
There are no proven methods to prevent canker sores from developing. Over-the-counter L-lysine is sometimes used. Good oral hygiene and avoiding hard, crunchy, or irritating foods may help to prevent canker sores that might develop as a result of irritation or trauma to the inside of the mouth.