Mouth ulcers have not stopped may be due to local irritants, malnutrition, immunity factors, psychological factors, etc. It is recommended to go to the hospital for specific examination and treatment. 1. Heavy wear of teeth with sharp edges will often cause rupture of the oral mucosa, forming mouth ulcers. 2. Due to partiality may cause malnutrition, the body lacks vitamin B, vitamin C, zinc, iron and other elements, often have ulcers. 3. Low immunity of the body, due to systemic diseases, immune cell response disorders, etc. are also prone to ulcers. 4. Psychological disorders, such as depression, anxiety, etc., often rest poorly will also recur ulcers. If the mouth ulcers are stubborn, they may also be caused by other reasons, and it is recommended to go to the hospital for examination and treatment in time.