This is what a single drop of the viper’s venom can do to blood
The venom of Russell’s viper has agents that can coagulate blood by activating factor V and factor X that converts prothrombin to thrombin. This solidification is why the venom is very efficient at inducing thrombosis, obstruction of blood supply by blocking the blood vessels, in the victims. Because of its coagulating capability, a diluted form of the venom is used in many hospitals for in vitro blood clotting tests. The venom is also given to horses or sheep in very small quantities to immunize and extract the resulting venom neutralizing antibodies from them to prepare antivenom.