Canker is a cyclic recurrent limitations as the characteristics of the oral mucosa ulcer damage, can self-healing, can occur in any part of the oral mucosa, with lip and cheek, tongue, severe cases can affect the pharyngeal mucosa. In many patients, with the extension of the course of disease, the ulcer area increases, the number increases, the number increases, the pain increases, the healing period lengthens, the interval is shortened, the influence food and the speech.
