Abstract --After the terroric attack in New York on Sep 11, 2001, the medical issues about chemical, biological, radiological, and nuclear terrorism became more and more important. In order to let all emergency personnel to be familiar with the cyanide poisoning, we reviewed articles about cyanide poisoning and introduced the effects of biologic destruction, metabolic mechanism, symptoms and signs of cyanide poisoning. Besides, we also put emphasis on the decontamination, laboratory diagnosis and treatment of cyanide poisoning. We hope this review article can give the readers enough information about how to approach patients exposed to cyanide and decrease the mortality and morbidity rate if there is a cyanide poisoning event.