Frequent oral ulcers are generally recurrent oral ulcers, the etiologic mechanism is not completely clear, and its onset may be affected by mental psychological factors, immune factors, dietary factors, etc., as follows. 1. Psychological factors: the occurrence of recurrent oral ulcers is related to the degree of psychological stress, anxiety, tension and other emotions have a certain role in promoting the occurrence of recurrent oral ulcers. 2. Immune factors: the occurrence of recurrent oral ulcers is related to the body’s immune level, when the body’s immune function decreases, it may lead to the incidence of recurrent oral ulcers increase. 3. Dietary factors: the occurrence of recurrent oral ulcers is related to an individual’s dietary habits. Deficiencies of iron, zinc, vitamins B1, B2, B12 and other nutrients may lead to recurrent oral ulcers. Recurrent ulcers may also have other causes, it is recommended to go to the hospital to receive professional targeted treatment.