Intravenous injection into the guinea pig of lethal doses of Echis colorata venom or of each of its two chromatographic fractions, separately, caused hemorrhage, afibrinogenemia, factor V deficiency and thrombocytopenia. Sublethal venom doses caused afibrinogenemia, factor V deficiency and thrombocytopenia in the absence of hemorrhage.
Early intravascular clotting was observed following injection of high lethal doses of both whole venom and of procoagulant-containing fraction II, but not of fraction I which was devoid of procoagulant activity.
The afibrinogenemia produced by fraction I was due to its fibrinogenolysin, whereas the afibrinogenemia produced by fraction II, which also had fibrinogenolytic activity, was due chiefly to its procoagulant.
Anti-Echis colorata venom rabbit serum inhibited the fibrinogenolytic, the procoagulant and the thrombocytopenic activities of the venom.