Cyanidforgiftning skyldes sædvanligvis udsættelse for røg ved ildebrand, indånding eller indtagelse af cyanid eller optagelse af cyanid fra huden eller slimhinderne (f. eks. i munden).
Cyanide poisoning usually results from exposure to smoke from fire, from breathing or swallowing cyanide, or from getting it on the skin or mucous membranes (moist body surfaces, such as the lining of the mouth).