Oral cancer is a general term for malignant tumors occurring in the oral cavity, most of which are squamous epithelial cell carcinomas, the so-called mucosal metaplasia. In clinical practice, oral cancer includes gum cancer, tongue cancer, hard and soft palate cancer, jaw cancer, floor of mouth cancer, oropharyngeal cancer, salivary cancer, lip cancer, and maxillary sinus cancer, as well as cancers occurring in the skin mucosa of the face. Oral cancer is one of the more common malignant tumors of the head and neck. For those who like betel nut chewing, if you find that the mucous membrane inside your mouth becomes white or gray, you often feel dry mouth, loss of taste sensation, numbness of lips and tongue, and burning pain of oral mucosa when eating spicy food can be tolerated. And feel the oral mucosa stiff, difficult to open the mouth, swallowing difficulties. Then you should pay attention! Then you may be suffering from oral submucosal fibrosis. This is because betel nut will slowly release a kind of irritant called betel nutin during the chewing process, which will cause submucosal fibrosis in the oral cavity, and this disease is an important risk factor for the development of oral cancer. The World Health Organization Cancer Research Center has warned the international community that chewing betel nut or betel nut will lead to oral cancer. According to the cancer registry report of the Department of Health in Taiwan, the mortality and incidence of oral cancer ranked seventh among the top ten cancers in Taiwan, and excessive betel nut chewing by pregnant women may also cause miscarriage. Oral submucosal fibrosis has a high incidence rate and is recognized by the medical community as a disease with a high risk of developing into cancer. Although nutritional deficiencies and low immunity are also factors that cause the disease, betel nut chewing is still the most important factor. There is no ideal treatment for this disease, currently relying mainly on drugs and surgery, but the results are not satisfactory. Eliminating betel nut consumption is the best way to prevent oral submucosal fibrosis and reduce the incidence of oral cancer.