Swelling of cheeks after eating betel nut is generally caused by betel nut containing irritants and overuse of chewing muscles. Betel nut is a kind of food that contains a lot of irritants such as demethyl betelin, high betelin, and crude fiber, which is harmful to the human body when consumed in large quantities for a long time. 1. The irritating chemicals contained in betel nut can irritate the oral mucosa. In addition, betel nut fibers will form sharp spines after chewing, which can easily puncture the gums and oral mucosa, thus leading to infections characterized by swelling. 2. Betel nut contains a large number of fibers, regular consumption of betel nut will be over-exercise the chewing muscles leading to chewing muscle hypertrophy, resulting in the formation of parotid swelling characteristics. Long-term consumption of betel nut is harmful to the human body, it is recommended to consume in moderation. If any uncomfortable symptoms occur, please consult a doctor for examination.