raising the efficiency of anticoagulant rodenticides "mineralocorticoid with a negligible glucocorticoid activity" mixed with chlorophacinone under laboratory conditions was studied. Results showed that the mortality percentage at albino rat Rattus norvegicus albinus increase with addition Astonin®-H (Ast.) to LD50 chlorophacinone, while the highest mortality were 90 and 100% at doses 70 and 90 mg/kg body weight Ast., respectively compared to 50% when chlorophacinone used alone at LD50. On the other side, the low doses of chlorophacinone 1/4LD50 alone or when added at different doses of Ast the mortality percentage was zero except at the dose of 100 mg/kg b.wt. caused 20% mortality. The bleeding time was increased gradually with increasing exposure time up to 120h then decreased. At the same time, prothrombin time increased to double when Ast. at doses 90 and 100 mg/kg b.wt. mixed with LD50 of chlorophacinone compared to use it alone. On the other hand, the plasma AST and ALT increased after 48h post-treatment than 24h compared to Pre-treatment for all treatments and there were significant differences between treatments after 24 and 48h. The highest value of AST and ALT recorded at dose of LD50+ 100 mg/kg b.wt. Ast. (90.35 and 31.12 U/L) after 48h of treatment, respectively.