It is possible that enteritis and mouth ulcers are related because some enteritis is manifested by inflammatory bowel disease, which means that there are ulcers inside the patient’s intestines, as well as bleeding, and ulcers may appear in other parts of the body, such as in the mouth. With a prolonged history, the patient’s skin may also be blackened, or there may be blackening inside the intestine. It is recommended that a colonoscopy and, if necessary, a pathological examination be taken to further clarify the diagnosis. If it is acute enteritis or chronic enteritis, it is considered to be a viral or bacterial infection that causes enteritis and is generally not related to the patient’s mouth ulcer. If it is caused by inflammatory bowel disease, it may be related to the mouth ulcer, and it should be treated systematically, because the treatment of inflammatory bowel disease as a whole is relatively troublesome.