Using venom proteinase inhibiting substance (ISV) on the venom of habu (T. flavoviridis), it was found that amounts of 30-240 .mu.g decreased 80% of necrosis and 60% of edema at maximum induced by 120 .mu.g of the venom, without any influence on hemorrhage, by i.m. method in rabbits (Fukami's method). Anti-venom proteinase serum (0.1 ml) inhibited edema and necrosis, but not hemorrhage, with the same amount of venom. Hemorrhage induced in mouse pad by the venom was studied by photometry. Dose-response curve for the hemorrhage was linear at < 15 .mu.g of venom. The results of inhibitory action of ISV on local lesions induced by the venom by mouse pad method indicated that 2.4 or 3.6 .mu.g ISV decreased lesions of edema, necrosis and hemorrhage. Proteinase of the venom was strongly correlated with necrosis, edema and hemorrhage. ISV was also a good tool for analyzing mechanisms of activities of various venoms.