I believe that we are not unfamiliar with mouth ulcers. When mouth ulcers attack, round or oval ulcer surface will be formed in the mouth, with grayish-white pseudomembrane on the surface, local burning pain of ulcers, blood blisters in the mouth, bad breath, swollen lymph nodes, etc., which will cause serious adverse effects on normal life and diet. Now mouth ulcers have slowly become one of the three major oral diseases of human beings. So we not only have to ask, what are the causes of mouth ulcers? Mouth ulcers occur with the following factors: First, exertion, stay up all night leading to a decline in the body’s resistance, may cause ulcers to flare up. Such as before and after the examination or after staying up late and other cases of higher incidence; two, the body lacks vitamin B1, vitamin B2, vitamin B6, vitamin B12 and folic acid and other vitamins, may induce mouth ulcers; three, the lack of micronutrients zinc, iron, the lack of folic acid, as well as nutritional deficiencies, etc., can reduce the immune function, increase the likelihood of the development of mouth ulcers; four, before and after the female menstruation, because of changes in hormone levels in the body may cause ulcers. Before and after women’s menstruation, because of the body’s hormone level changes may cause ulcers; five, the body’s immune system disorders, cited easy to cause mouth ulcers. Sixth, the real fire or false fire caused by the fire caused; seventh, the factors of trauma, a common cause is the teeth bite, especially the teeth are not aligned most likely to occur this phenomenon; eighth, the occurrence of mouth ulcers are also related to genetic factors, mental factors, food, drugs and other factors. The causes of mouth ulcers are complex and varied, and each person’s physical condition is different, and the triggers of their mouth ulcers are also different, so they are not the same in treatment.