Studies on pre-clinical toxicity were undertaken to determine the haematological and biochemical changes after administration of alcoholic extract of leaf-stalk of P. betle in rats and mice. Acute and chronic toxicity experiments were performed on mice and rats according to WHO protocol. Different doses of plant extractive were administered for toxicity studies on short and long term basis. Haematological, biochemical profiles and enzymatic studies (transaminases and phosphatases) indicated that the drug (plant extractive) was devoid of toxicity.