Canker sores, or aphthous ulcers, can affect the tongue and other parts of the mouth. A canker sore on the tongue can be painful and make eating difficult. Topical treatments and...

A canker sore is a small, shallow, open wound or ulcer in your mouth that can make eating and talking uncomfortable. It is also known as a mouth ulcer or aphthous ulcer.

Canker sores, also called aphthous ulcers, are small, shallow lesions that develop on the soft tissues in your mouth or at the base of your gums. Unlike cold sores, canker sores don't occur on the surface of your lips and they aren't contagious.

Canker sores — or aphthous ulcers — are small, shallow ulcers that occur in the lining of your mouth. A canker sore starts as a white or yellowish mouth sore with a red border. They’re usually very small (less than 1 millimeter) but may grow to 1/2 inch to 1 inch in diameter.

An aphthous ulcer is typically a solitary round or oval punched-out sore or ulcer inside the mouth on an area where the mucosa is not tightly bound to the underlying bone, such as on the inside of the lips and cheeks or underneath the tongue. Aphthous ulcers can also affect the genitalia in males and females.