Arecae Semen is in use in Korean medicine. The Korean medical doctors use Arecae Semen for destroying intestinal worms(殺蟲), removing stagnation of food(消積), etc. We investigated toxicity, poisoning symptoms, poisoning treatment and prevention against poisoning of Arecae Semen. The results were summarized as follows: 1.The main ingredients of poisoning are arecoline, arecaidine, etc. The ingredients of poisoning from Arecae Semen mainly can cause stimulating symptoms on digestive system, nervous system, respiratory system, circulatory system and urinary system, etc and those can cause the production of cancer. 2. The representative methods of poisoning treatment are washing out the stomach, supplies of grape sugar and symptomatic treatment, etc. 3.In order to prevent against poisoning of Arecae Semen, the patients should keep usage, dosage and notes.