A canker sore, or aphthous ulcer, is a small round or oval-shaped sore that develops inside the mouth, including the tongue, cheeks, lips, or on the roof of the mouth. Canker sores have a white or ...
Canker sores, medically referred to as aphthous ulcers, can be a painful nuisance. These small, shallow ulcers appear in the mouth, making eating and talking uncomfortable. Although the exact cause ...