It is true that long-term betel nut chewing may cause cancer. Betel nut contains a large number of alkaloids with strong cytotoxicity, which will damage the health of the oral mucosa. Long-term consumption of betel nut will lead to fibrosis of the oral mucosa, which will increase the chances of developing oral cancer. Betel nut tannins, betel nut-specific nitrosamines and reactive oxygen species can be detected in the saliva of betel nut chewing people, which have carcinogenic potential. Chewing betel nut for a long time will also lead to serious wear and tear of teeth, triggering a series of oral diseases such as periodontitis, thus increasing the risk of oral cancer. Moreover, in order to make betel nut taste better, merchants often add ephedrine, quicklime, etc. Ephedrine is a kind of alkaloids, while quicklime contains lead, mercury and other heavy metals. Long-term consumption will cause poisoning phenomenon, may also damage the oral mucosa, make it abnormal proliferation and mutation, increase the chance of cancer. Although betel nut has some medicinal value, excessive consumption will cause great harm to the human body. If a patient develops betel nut addiction or oral diseases, it is recommended that he or she seeks treatment in a timely manner.