”Betel nut on the tall tree, whoever climbs it first will taste it first.” This is a familiar Taiwanese love song. Nowadays, betel nut is not only a special food in Taiwan, but also popular in Hunan, Hainan, Fujian and other places. It is said that chewing betel nut can be mouth and tongue, refreshing, easy to eat after the euphoria, a sense of relief, as a snack, loved by men. However, long-term betel nut chewing can cause submucosal fibrosis (mouth opening), which is a direct cause of oral cancer. Why does this small fruit cause cancer? It turns out that betel nut contains a lot of betel nutin and alkaloids, which are cytotoxic. The reaction between the oral mucosa and the alkaloids contained in betel nut will lead to fibrosis of the oral mucosa, which is clinically manifested as difficulty in opening the mouth, numbness, ulcers and so on. In addition to betel nut, tobacco and alcohol are also inseparable from oral cancer. Those who chew betel nut, smoke and drink alcohol at the same time will have a much higher risk of oral cancer. It is reported that 300,000-400,000 new cases of oral cancer (oral cancer or oropharyngeal cancer) occur each year worldwide, of which 228,000 cases occur in South and Southeast Asia, accounting for 58%, while a survey released by the WHO Cancer Research Center shows that 60% of oral cancer may originate from betel nut chewing, and Taiwan and India are listed as endemic areas of oral cancer caused by betel nut eating. Therefore, we remind many people who love to chew betel nut: the first shot to prevent cancer, do not take betel nut as ice sugar.