Mouth ulcers are very common diseases of the oral mucosa that are recurrent and self-healing. Generally, mouth ulcers will appear as red, yellow, concave and painful on the surface. For the treatment of mouth ulcers, it is important to carry out topical treatment, which means spraying the surface of mouth ulcers with medications for ulcers, such as open throat sword spray, watermelon cream and Yunnan Baiyao tablets. In addition, oral hygiene should also be kept clean by rinsing with chlorhexidine mouthwash. Frequent mouth ulcers may be related to low body resistance, so it is recommended to take drugs to improve resistance, such as transfer factor, pidomod, etc. There are also some mouth ulcers that are related to systemic diseases, such as Leukocerebrosider’s syndrome, and if they are such ulcers, they should be treated for systemic diseases.