Aphtha, a common infantile oral disease, is clinically marked by small yellowish and whitish or grey ulcer on oral and lingual mucous membrane, and local burning pain. If the mouth cavity is full of erosion, it is called "koumi" (oral erosion) ; if the ulcer occurs only on the bilateral sides of the mouth and lips, it is termed as"yankou-chuang" (perleche). The disease may occur alone or together with other diseases. It pertains to the categories of "ulcerative stomatitis", "herpetic stomatitis" and "mouth angular stomatitis"in modern medicine. The disease is favourable in prognosis. If the patients with weak physique, the disease may occur repeatedly, and is lingering and intractable.