When mouth ulcers are bad for a long time, it is important to distinguish whether the ulcers are recurrent and have been bad, or whether the ulcers in a single area persist and have been bad. Generally what we call a mouth ulcer is a clinical symptom, but it is more of a clinical disease that we call recurrent mouth ulcers, also known as oral aphthous ulcers. Its typical characteristic is that it will have obvious self-limiting and recurrent, the so-called self-limiting means that this kind of ulcers even without any treatment, about 2 weeks of time will be significantly improved, but this kind of ulcers are difficult to eradicate, often in 1 part of the improvement, after a period of time in other parts of the re-emergence, so it is called recurrent, this kind of ulcers is a very common clinical disease, many patients will exist The ulcers are very common in the clinic, and many patients have them, but there is no need to worry too much about them, they are treated symptomatically. But if it is a single part of the ulcer, persisting for a long time is not good, then 1 must be alarmed. This is because there is a possibility that it is not just a recurrent ulcer, but an oral tumor, and if necessary, a pathological biopsy can be performed to clarify the diagnosis.