The main reasons for mouth full of mouth ulcers are as follows: 1, some diseases of the immune system, such as the most common Leukocyte syndrome or late AIDS, will appear mouth full of mouth ulcers; 2, simple fire can cause mouth full of mouth ulcers; 3, the mouth is not too clean, such as food residue residue, or oral disease caused by mouth ulcers; 4, itself is older, relatively poor absorption function, vitamin B family and vitamin C and other nutrients are poorly absorbed, which in turn leads to mouth ulcers; 5, some patients have immune diseases, with immunosuppressants and other drugs, the immune system is in a very low state. And in the case of very low immunity, it will induce mouth full of mouth ulcers, so specific problems should be analyzed specifically. The first thing to look for in a mouth full of ulcers is whether the patient is male or female, how old the patient is, whether there is any other underlying disease, and how long the ulcer has lasted. The general public will think that this is a fire, but in reality it can not be fully explained by a fire.