In daily life, almost everyone has the experience of oral erosion or ulcers. Eating thin rice or drinking hot tea in a hurry may burn the oral mucosa, catching a cold and fire, overexertion and trauma can lead to ulceration of the oral mucosa, but sometimes oral ulcers occur for no reason. If it occurs once or twice occasionally, it may not be on the mind. However, if repeatedly occurring many times, it can be taken seriously, it is best to find a professional doctor to confirm whether it belongs to one of the following: 1, Aphthous stomatitis: refers to the oral mucosa single or multiple isolated round or oval superficial ulcers, accompanied by intense spontaneous burning-like painful disease. The course of the disease is self-limiting, the etiology is unknown, and may be related to infection, allergy, endocrine, psychiatric and genetic factors. Often manifested only as oral lesions, no other systemic symptoms, and the needle isomorphic reaction negative. 2, herpes stomatitis: caused by the herpes virus, small herpes in the gums, buccal mucosa, tongue and palate, pharynx, herpes ulcerated into ulcers, covered with yellowish secretions, next to a ring of red. The ulcers are shallow in and confined to oral lesions. Herpes fluid taken for viral testing is often found to be positive for herpes simplex virus-1. 3. Leukoplakia: a triad of oral and external genital ulcers and iritis based on the pathology of microvascular vasculitis. About 70% of patients first develop oral ulcers, and the incidence of oral ulcers is up to 95% or more throughout the course of the disease. The ulcers may be single or multiple, 2-10 mm in size, round or oval in shape, with a yellowish necrotic base in the center, surrounded by a bright red halo, and may heal spontaneously, mostly without scarring. Multi-system damage may also occur: ocular lesions, skin damage, arthritis, neurological lesions, urethritis, interstitial pneumonia, myocarditis, non-specific gastroenteritis and ulcers, epididymitis, etc. Needle prick isomorphic reaction is often positive. 4, common aspergillosis: a relatively serious chronic recurrent autoimmune maculopapular skin disease of the skin mucosa characterized by the loosening of intraepidermal acanthocytes. About 50%-70% of patients develop oral mucosal damage, which is one of the important clinical manifestations of the disease, mostly involving the cheek, palate, lip or floor of the mouth. The damage appears with sensory sensitization, burning pain, dry mouth, and swallowing inconvenience, followed by the appearance of soybean to walnut sized blisters on the easily abraded areas, which are thin-walled and easily ruptured, leaving a grayish-white film. The vesicular surface bleeds easily, the burning pain is obvious, and the amount of saliva increases. The vesicular surface is difficult to heal and sometimes develops into an ulcer, which affects feeding, chewing and swallowing. It is also accompanied by skin damage.