Under normal circumstances, eating betel nut will not cause poisoning, but if the number of betel nut is relatively large or some people are allergic to betel nut ingredients, the symptoms of poisoning will occur when eating betel nut in this case. The reason for the poisoning of betel nut is that betel nut contains a variety of alkaloids, which can cause damage to the human digestive tract and nervous system after entering the body. The alkaloids do not cause serious damage when betel nut is taken in normal doses, and there are no obvious symptoms after eating it. However, if a large amount of betel nut is taken, the accumulation of this alkaloid in the body will lead to poisoning. In addition, betel nut poisoning is mainly characterized by headache, dizziness, nausea, vomiting, abdominal pain, diarrhea and other symptoms, and in severe cases, blurred vision, numbness of the mouth and tongue, twitching of the limbs and other phenomena. Patients with betel nut allergy will have rash, itchy skin, swelling of the face and other symptoms, which will seriously affect the respiratory system and cause respiratory difficulties, so rescue measures should be taken in time.