Oral ulcers may be related to many occurrences.

Most doctors believe that oral ulcers may be related to the occurrence of the following five factors:
First, digestive system diseases and disorders, such as abdominal distention, diarrhea or constipation, and so on.
Second, the endocrine changes. Some women during menstruation or walking around there will be oral ulcers, drug treatment can only be temporarily eased, still appear next month when passing through. At the same time, frequently dry mouth, upset, irritability and dry stool guitar. This may be the pre-menstrual and progesterone levels increase, the lower the level of estrogen-related. Studies have shown that in the period before the recurrent oral ulcers in patients given estrogen therapy, received good results. The pregnancy of women, estrogen levels will rise, so often attack oral ulcer patients during pregnancy symptoms will be significantly improved.
Third, the mental element. Some patients in the spirit of tension, mood changes, sleep in poor circumstances will the incidence, and this may be related to autonomic dysfunction.
Fourth, genetic factors. If both parents are suffering from recurrent oral ulcers, their children about 80% -90% probability of suffering from the disease; if breast cancer was one of the parents when their children about 50% -60% probability of illness.
Fifth, the other factors. Including the lack of zinc, iron, folic acid, vitamin B12, may reduce the immune function, thereby increasing the recurrent oral ulcers the possibility of disease.