Tin class San can treat mouth ulcers, the main ingredients include Qing Dai, ice chips, artificial sulfur, etc. It has the effect of clearing heat and detoxifying, resolving decay and creating muscle, and is used to treat mouth ulcers, which can promote ulcer repair and healing. The causes of mouth ulcers are complex, related to mechanical injury, abnormal autoimmune function, mental and neurological factors, and possibly infectious factors, so the most important treatment for mouth ulcers is to actively search for the cause, remove the cause, and then treat the symptoms to promote healing. For the mouth ulcer itself, generally use drugs to prevent infection and promote healing, commonly used including patches, such as the Italian can paste or gentamicin film, the effect is good. From the point of view of Chinese medicine, nourishing Yin and Shengjin San and tin class San are useful for treating mouth ulcers, and after clinical observation, the effect is more certain, but we should pay attention to the correct use method to avoid adverse reactions.