Rattlesnake bite is most common in young men who often are intoxicated and have purposely handled a venomous snake. The incidence of bites is highest in the spring and early summer months, and they most often occur in the afternoon. The hands and feet only are involved in 95% of all bites. First-aid therapy should be limited to splinting the extremity and transporting the victim to a medical facility. Definitive therapy is administering antivenin (Crotalidae) polyvalent intravenously in adequate initial doses and repeating every two hours until the venom is completely neutralized. Serum sickness usually follows all doses of more than five vials but is readily controlled by giving corticosteroids. Bites are avoided by protecting the hands and feet, not handling venomous snakes, and using utmost caution while in the snakes' habitat.