Mean value of this snake group. Snakes were collected from snake husbandry unit, snake farm of Queen Saovabha Memorial Institute (QSMI). Dried venom. The liquid (fresh) venom was weighed immediately before frozen at -20°C and lyophilized by Freeze Dryer (Modulyo, EDWARDS). Swiss albino mice (18-20 g) were obtained from laboratory animal unit of QSMI. The lethal toxicity of the venom was determined by intravenous injection of 0.2 ml of serially 1.4 fold-diluted venom solutions into the tail vein of mice. The LD50 was calculated by the method of Reed-Muench (1938) and 95% confidence limits by the method of Pizzi (1950).