The problem of pitviper bite in field researchers working in Middle America (Mexico to Panama) was studied using case histories of nine biologists and one project employee bitten during the period of 1980 to 1991. All snakes involved were Bothrops asper. Based on local tissue and systemic effects, seven cases were severe, there ith permanent disability. There were no fatalities. Although antivenom was administered intramuscularly as field treatment to seven victims and later intravenously as hospital treatment to nine as patients, its effect on outcome was uncertain. Nevertheless, intramuscular antivenom is recommended following an adult Bothrops asper bite when there are signs of envenomation and travel time to a treatment facility is more than four hours