Regular consumption of betel nut is definitely harmful to the human body at present because betel nut was defined by the World Health Organization as a class 1 carcinogen more than a decade ago. Like nicotine, betel nut is a substance that has a clear carcinogenic effect on the human body, but there are still many organizations selling betel nut for various reasons, especially economic reasons, which is actually very dangerous. For the oral cavity, betel nut can lead to a significant increase in the risk of oral cancer. Long-term chewing of betel nut can lead to a specific disease of the oral mucosa called oral submucous fibrosis, which usually occurs only in patients who chew betel nut for a long period of time. Submucous fibrosis causes the oral mucosa, especially the buccal and lingual mucosa, to harden and toughen, causing an obvious burning sensation in the oral mucosa, and in severe cases, limiting the opening of the mouth. In this case, it is many times more likely to become cancerous than our normal mucosa. There are no good treatment options for oral submucous fibrosis.