The common causes of ulcers at the corners of the mouth include infection, immunity, heredity, trauma, anxiety, etc. Its occurrence is also related to menstruation and low resistance. 1. If a bacterial infection, such as Candida, occurs, the corners of the mouth will be prone to ulceration due to the moistness of the corners of the mouth, resulting in ulcers at the corners of the mouth. 2. Trauma, when improper diet abrasion or food spicy irritation of the corners of the mouth, will also be prone to ulcers. 3. Anxiety, depression and other mental factors, also easy to cause mouth ulcers, common such as stress white-collar workers. 4. Women are also prone to mouth ulcers during menstruation due to changes in hormone levels and low immunity. When ulcers occur, it is recommended to consult a doctor in time, and then according to the cause of the cause of the symptomatic treatment.