Oral mucosal fibrosis is a very common oral disease, for whatever reason, I believe that many people have had oral ulcers. Generally, oral mucosal fibrosis can be cured within 1~2 weeks after effective treatment, but some oral mucosal fibrosis does not improve even after several months, so we need to be alert that oral mucosal fibrosis has become a precursor of oral cancer. How do we distinguish common oral ulcers from early symptoms of oral cancer? 1.Differentiate from morphology and quantity The shape is more regular, round, oval or linear, with neat and clear edges and clear demarcation with surrounding tissues, and the sunken base is smoother and soft to touch, and the pain is obvious, which is mostly benign, i.e. common oral ulcer. Malignant form is more irregular, the boundary is unclear, the edge is elevated in an uneven shape, the bottom of the ulcer is not flat, granular, feel some hard, different from other parts, and the ulcer is not painful or less painful. 2, from the frequency of attacks and time to distinguish benign mouth ulcers generally 1-2 weeks to heal. If it takes longer than two months to heal, or if the attacks are frequent, more than twice a month, you need to go to the hospital as soon as possible to identify the cause. 3, from the drug after the response to distinguish benign mouth ulcers correctly use the drug effect is obvious, can accelerate the healing, malignant is not obvious. In addition, some people do not find the exact cause of the medication, the result of ulcers not only did not improve, but also more and more serious.