snake venom [AS, snacan + L, venenum] , a poison produced in glands of certain snakes and injected through fangs into a victim’s flesh. The exact composition of snake venoms varies with different species, but generally they are complex mixtures of neurotoxins, proteolytic enzymes, and phosphatases. About 20 of more than 100 North American species of snakes are venomous, accounting for about 8000 snake venom poisonings a year. A venomous snakebite is considered a medical emergency.