Myonecrotic and oedema-inducing activities of Bothrops jararaca of Argentina were studied. For oedema-inducing activity 0.05 ml of different solutions of venom in 0.9% NaCl were injected in mice. The dose of 0.86 micrograms/20 g mouse induced an oedema of 30% respect the other member in one hour. The myonecrotic effects were studied injecting mice gastrocnemius muscle with 70 micrograms of venom in 0.1 ml of 0.9% NaCl, which were sacrificed in different time. The inoculation area was obtained for hystophatological process. Animal sacrificed 30 minutes after the inoculation showed oedema, hemorrhage and inflammatory infiltrate. Those sacrificed in one and three hours after the inoculation also had got necrosis.