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What Are Canker Sores?

Canker Sore

Say: KAN-kur

This is a small mouth sore that's a big pain. Canker sores are open sores that have a white or yellowish coating and are usually about ¼ of an inch across. You might find them on the inside of your lips and cheeks, at the base of your gums, and on or under your tongue.

Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.