Aphthous stomatitis, commonly known as canker sores, is a condition characterized by the appearance of small, painful ulcers in the mouth. These sores can occur on the inner cheeks, gums, tongue, and the roof or floor of the mouth. The exact cause is not fully understood, but factors such as stress, certain foods, and nutritional deficiencies may contribute to their development. These ulcers typically heal on their own within one to two weeks and are not contagious. Treatment focuses on relieving pain and discomfort, often using topical medications or mouth rinses. Maintaining good oral hygiene and avoiding irritants can help prevent future outbreaks.