Fil: de Roodt, Adolfo R. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Producción de Biológicos; Argentina.Fil: Dolab, Jorge A. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Producción de Biológicos; Argentina.Fil: Dokmetjian, Christian. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Producción de Biológicos; ArgentinaFil: Litwin, Silvana. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Producción de Biológicos; Argentina.Fil: Segré, Liliana. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Producción de Biológicos; ArgentinaFil: Vidal, Juan C. Museo Argentino de Ciencias Naturales Bernardino Rivadavia. Area lología; Argentina.The hemorrhagic activity of Bothrops (B.) alternatus, B. ammodytoides, B. jararaca, B. jararacussu, B. moojeni and B. neuwiedii venoms from specimens captured in Argentina was assayed after i.d. injection to mice. The hemorrhagic haloes produced by each venom had different color intensities, although no significant differences were observed by measurement of the average diameters or the weight of the excised hemorrhagic haloes. Conversely, important differences were found by measuring the amount of hemoglobin extracted from excised hemorrhagic haloes of similar size produced by different venoms. The relationship between the amount of hemoglobin extracted and the weight of the excised hemorrhagic haloes was linear, with a slope (hemoglobin released per gram of hemorrhagic halo) characteristic for each venom, and proportional to the potency. On this basis, the activity of B. alternatus, B. ammodytoides and B. jararaca is similar, about 1.5 times higher than that of B. jararacussu and B. moojeni venoms and threefold higher than that of B. neuwiedii venom. Thus, measurement of the of hemoglobin released provides additional information in comparative studies, and may be used to assess the antihemorrhagic potency of antivenoms.