Snake venoms are complex mixtures of proteins and non proteins components. This study evaluated the toxicity effect of LD50 of native Echis coloratus venom and the LD50 of dry venom irradiated with different doses of gamma radiation (2, 5 & 10 KGy) on Swiss albino mice. Measurement of some biochemical parameters and histological alterations in liver and kidney was investigated. The biochemical parameters showed highly significant increase (P< 0.001) in levels of ALT, AST, urea and CK in all groups compared to control group. Levels of serum creatinine showed highly significant increase (P< 0.001) in groups treated with LD50 of crude venom and 5 times LD50 of irradiated venom at 2 and 10 KGy, But, showed significant (P< 0.05) with groups treated with 5 times LD50 of irradiated venom at 5KGy & LD50 of irradiated venom
at 10 KGy showed non-significant in group treated with LD50 of 5KGy & 2KGy compared to control group. Histological examination showed alterations in liver, kidney in mice injected with crude venom compared to control group. Also, the group of mice which injected with different doses of irradiated venom showed no histopathological alteration in liver and kidney tissues, except the mice group injected with 5 times LD50 of irradiated venom at 2 KGy and the group which injected with 5 times LD50 of irradiated venom at 10 KGy which showed alterations in liver and kidney tissues.