Mouth ulcers are ulcerative diseases of the oral mucosa due to a combination of immunologic, genetic, nutritional metabolic, psychological and other aspects. Simply applying vitamin C externally is largely ineffective, and to the heavier. Because in general the onset of oral ulcers itself has a cyclical, from the beginning of the onset of the disease to the complete improvement, the middle of the relatively heavy time, but oral ulcers have its self-limiting, that is, even if you do not do the treatment, the ulcers can achieve clinical healing, that is, oral ulcers in the 1-2 weeks between the non-treatment can also be healed. Clinical attention should be paid to the need for pathologic biopsy of ulcers that are fixed in place for a long period of time and that grow progressively.