Long-term mouth ulcers may be caused by the lack of micronutrients, resistance decline, etc., according to the cause of the disease can be supplemented with vitamins, enhance resistance and other methods of root treatment. Long-term mouth ulcers can be applied locally to promote ulcer healing drugs, such as tretinoin gel or watermelon cream spray to promote local healing of ulcers. In order to cure the disease, we need to treat the symptoms according to the cause of the disease, the details are as follows: 1. Supplementary vitamins: if the patient lacks certain trace elements may lead to long-term mouth ulcers, this time you need to supplement the trace elements, oral vitamin B and so on. 2. Enhance the resistance: the patient’s body resistance to decline, long-term late night and other reasons can also cause long-term mouth ulcers, this time you need to supplement the body to enhance the resistance of the drug, such as transfer factor, etc., it is recommended that the patient should maintain a regular routine, do not stay up all night, do not eat spicy and stimulating food, etc.. The above medications should be used under the guidance of a doctor, if the symptoms of long-term mouth ulcers are serious or have not been improved, it is recommended to go to the hospital in time for treatment.