The enzymatic properties of Factor II (FII) and Factor X (FX) activators from Bothrops erythromelas venom were investigated. Both activators were inhibited by ethylenediaminetetraacetate (EDTA) and 1,10-phenanthroline, and are thought to be metalloproteinases with molecular weights of 90 kDa and 70-90 kDa, respectively. The activity of the FII activator in the crude venom was about 30 times greater than that in Oxyuranus scutellatus venom and the level of FX activator activity, which was CA2+ ion dependent, was similar to that in Daboia russelli venom. The venom also had two haemorrhagic factors (58 and 105 kDa) and two fibrinolytic enzymes (18 and 58 kDa).