Oral ulcers are one of the most frequent diseases of the oral cavity, and there are many reasons for the occurrence of oral ulcers, the most common being recurrent oral ulcers (also called recurrent mouth sores), followed by traumatic oral ulcers caused by various traumas (such as unsuitable dentures, stimulation of sharp edges of the residual roots and crowns of teeth, etc.), oral mucosa cancer and some special infections (such as tuberculosis, syphilis, etc.) can also lead to the occurrence of oral ulcers. I. Recurrent oral ulcers Recurrent oral ulcers are superficial ulcers repeatedly occurring on the oral mucosa, round or oval, the size of which can range from rice grain to soybean size, the ulcer surface is depressed, the surface is covered with yellowish pseudomembrane, and the surrounding area is circularly congested, the disease is self-limiting, that is, the ulcer can generally heal itself in one to two weeks after occurrence. The disease is self-limiting, i.e., the ulcers usually heal themselves in one to two weeks after they occur. Since oral ulcers recur periodically, it is called “recurrent oral ulcers”. It can occur several times a year, or several times a month, or even alternate between old and new ulcers. The cause of the disease is not clear to the medical community, but it is proved through research that the occurrence of recurrent mouth ulcers is often related to the following factors: malnutrition, vitamin deficiency, micronutrient deficiency, such as iron, folic acid, B12 and zinc deficiency; endocrine disorders, such as women in the menstrual period due to the increase in the level of luteinizing hormone and estrogen (progesterone, etc.) level is reduced prone to mouth ulcers; neurological Mental factors, such as work strain, mental tension fluctuations, neurological disorders, etc.; digestive system diseases, such as constipation, diarrhea and inflammation of gastrointestinal ulcers, etc.; in addition, there is also a relationship with heredity, the disease has a clear tendency of family inheritance, because we often find in the clinic, if one or more parents suffer from recurrent oral ulcers, then their children are more prone to the disease than the general population. The diagnosis of recurrent oral ulcers is based on the above clinical features and periodic recurrence. Since the etiology of the disease is not very clear, and the occurrence of the disease is related to a variety of factors in the whole body of the individual, it is very difficult to cure the disease at the current medical level, once the mouth ulcer occurs, although there are many treatment methods, but basically all are symptomatic treatment, the purpose is to promote ulcer healing, reduce pain or reduce the number of recurrence, so the main treatment method is to use a variety of drugs to promote ulcer healing ( Therefore, the main treatment method is to use various drugs that promote ulcer healing (such as Beflex, oral ulcer film, etc.) to accelerate ulcer healing and shorten the duration of the disease. Although recurrent oral ulcers are difficult to cure, their incidence can be greatly reduced if the triggering factors are avoided as much as possible. We suggest that patients suffering from recurrent mouth ulcers should pay attention to the following aspects: 1, usually pay attention to the protection of oral hygiene, eat more vegetables, fruits to supplement a variety of vitamins, eat less barbecue fried and greasy food, do not eat spicy and hot food such as chili, raw onion, ginger, garlic, tobacco, wine, mutton, etc., in addition should be supplemented by diet milk, eggs, wheat germ and other foods to zinc, iron and other trace elements. 2, due to excessive fatigue and mental tension is a common cause of mouth ulcers, so try to avoid anxiety, keep a relaxed mood, optimistic and cheerful, avoid excessive fatigue, to ensure adequate sleep. 3, life and living should be regular, to develop certain bowel habits, appropriate more water to prevent constipation, if suffering from inflammatory diseases of gastrointestinal ulcers, should actively cooperate with the relevant treatment. 4, many young and middle-aged female patients, mouth ulcers more fixed occur in the period before (or after) menstruation, which is due to the reduction of estrogen in the body, so these women must pay attention to maintenance, to consume enough protein, to often eat natural foods that can supplement estrogen, such as soy, onions, etc., so as to maintain the normal secretion of estrogen in the body. Second, traumatic oral ulcers oral ulcers can also be caused by dental bites, damage when eating, the presence of unextracted residual roots, residual crowns or wearing unsuitable dentures in the mouth, the sharp edges of which constantly stimulate damage to the oral mucosa, resulting in traumatic oral ulcers occur. The cause of traumatic oral ulcers is clear, and the treatment is mainly to eliminate the cause, and then the ulcers can be healed with drugs that promote the healing of ulcers. If traumatic oral ulcers are not removed, the ulcers will not only not heal, but also get worse, and this kind of ulcers that do not heal are a kind of precancerous lesions, which can lead to cancer. Therefore, patients with frequent traumatic oral ulcers should try to avoid eating too hard and too hot food, eat not too fast, and if there are irritants such as root remnants, crown remnants or unsuitable dentures in the mouth, they should be treated and eliminated in hospital as soon as possible. Third, cancerous oral ulcers and infectious oral ulcers Genetic mutations can occur in normal oral mucosa, leading to the occurrence of cancerous ulcers, cancerous oral ulcers can also be formed by the development of some oral mucosal diseases such as lichen planus, white spots, erythema and long-term non-healing traumatic ulcers. Some special infections such as syphilis and Mycobacterium tuberculosis can also cause the occurrence of oral ulcers. The base of the above oral ulcers is generally hard, and if there are oral ulcers with a hard base, they should be treated at the hospital as soon as possible. In addition, oral ulcers of leukemia, lupus erythematosus, AIDS infection, neutropenia and other diseases can also appear as concomitant symptoms and should be given high attention. In conclusion, oral ulcers can be caused by local causes or systemic diseases, but they can be minor or major diseases. Regardless of the causes, oral ulcers that do not heal in more than 2-3 weeks should go to the hospital for regular examination and treatment.