Mouth ulcers may be caused by infections, micronutrient deficiencies, and other reasons. Therefore, the medication for mouth ulcers must be administered according to the different causes so that the best medication effect can be achieved. There is no one medication that can treat all mouth ulcers. Bacteria and fungi can infect the mucous membrane of the mouth and cause mouth ulcers. For mouth ulcers caused by bacterial infections, it is necessary to pay attention to maintaining oral hygiene, eating a light diet, controlling oral flora and avoiding local irritation to help the ulcerated mucosa heal itself. For mouth ulcers caused by fungal infections, the treatment process can be carried out by directly rubbing with phytomycin, and using sodium bicarbonate can also change the living environment of fungi to kill them. Drugs must be used under the guidance of a doctor. It is not uncommon for mouth ulcers to be caused by micronutrient deficiency. In particular, some B vitamins, folic acid deficiency and iron deficiency can lead to the development of mouth ulcers and are not uncommon. To treat mouth ulcers caused by these types of causes, treatment can be given in time with supplements, vitamin B complex, methylcobalamin, folic acid, and various types of iron supplements can be used depending on the situation. With proper supplementation, the effect is very good and visible results can be seen in the short term. There are many reasons for the occurrence of mouth ulcers, and as long as the cause of the occurrence can be clearly diagnosed, attention can be paid to lifestyle and dietary habits, and targeted medication can be given when necessary, all of which can quickly provide good treatment results. The key to evaluating the goodness of medication is to be able to treat the cause effectively.