The main reasons for frequent mouth ulcers are as follows: First, the lack of vitamins and trace elements in the body, commonly found in people who are picky eaters and partial eaters, and the lack of B vitamins, vitamin C, vitamin E and iron, zinc and selenium in trace elements in the body can easily induce mouth ulcers. Second, incorrect eating habits, such as like to eat spicy, irritating and high temperature food, is easy to suffer from ulcers. Third, incorrect work and rest habits, seen in the long-term stay up late, black and white reversal of the crowd, because these people will have immune disorders, will also suffer from mouth ulcers. Fourth, there are dental diseases in the mouth, such as too sharp tooth tips, root remnants or bad restorations, which can often bite or scrape the mucous membrane in the wound, causing traumatic ulcers.