There are many types of mouth ulcers, and the more common ones are recurrent mouth ulcers, i.e. recurrent aphthous ulcers. Mild recurrent aphthous ulcers can heal on their own in 7-10 days; while herpetic recurrent aphthous ulcers can last up to 10-14 days before they heal on their own; in severe cases, the disease can last 1-2 months or even longer before it gets better, at which point it requires doctor intervention and is more difficult to heal on its own and can recur. In addition to the above, the following causes of mouth ulcers, but whether self-healing and self-healing time varies from person to person. I. Traumatic oral ulcers: 1. mechanical injury: such as wisdom teeth, stumps and other bites or fish spines and other hard substances scraped and caused by oral ulcers, such oral ulcers and recurrent aphthous ulcers similar course, as long as to reduce stimulation, completely remove the traumatic factors, 7-10 days can be self-healing; 2. drug injury: such as the use of aspirin and other tablets or iodine tincture and other irritating drugs, may cause local oral Mucosal damage, usually 7-10 days after the cessation of drugs can be self-healing; 3, other injuries: hot and cold stimulation, such as water temperature, food too hot or low temperature treatment caused by mucosal burns or frostbite, usually 7-10 days after the removal of stimulation can be self-healing. Second, the disease accompanied by oral ulcers: 1, tuberculosis ulcers: such ulcers irregular shape, rat-like, accompanied by signs and symptoms of tuberculosis, performance for a long time, the need for treatment of the original disease, and then improve the symptoms of oral ulcers; 2, cancer ulcers: long course, usually several months or even a year can not heal themselves, and accompanied by fever, anemia and other systemic symptoms. C. Other oral ulcers: the symptoms of oral ulcers of Behçet’s syndrome are similar to those of recurrent Aphthous ulcers, and the recovery time is basically the same, but the eyes and skin can also be involved, and in severe cases, they cannot heal themselves and need to be treated; some patients have a history of radiation exposure, which can cause radiation stomatitis, which can heal itself 1-2 weeks after stopping radiation. It is usually not recommended to wait for self-healing after the appearance of mouth ulcers. Pay attention to oral hygiene to avoid re-injury, or use topical or oral medication to relieve symptoms under the guidance of a doctor or pharmacist. If an ulcer appears for a long time or gradually expands, you should seek medical attention as soon as possible to determine if the disease is causing the lesion.