The common clinical mouth ulcers, also known as aphthous ulcers, are typically recurrent, so it is determined that they will recur. In addition to recurrence, the ulcer has typical self-limiting, even without special treatment, the ulcer will heal naturally in about 1-2 weeks, but it is difficult to eradicate, and it will not take long for the ulcer to recur again, are typical of recurrent oral ulcers. Typical clinical manifestations are often covered with a yellow pseudomembrane in the middle, slightly depressed, slightly red and swollen around, accompanied by more intense pain, especially irritation pain will be more intense, ulcer patients in eating and talking once touching the ulcer, pain will be very intense.