Lambda-cyhalothrin which is a recent pyrethroid insecticidal agent, elicited a concentration dependent negative inotropic and choronotropic effects on isolated perfused rabbit heart with an increase in coronary outflow which might be of cholinergic nature. A relaxant effect was achieved on the rat thoracic aortic strip preparations which was abolished in presence of atropine indicating the acetyl choline like effect of the compound. Lambda- cyhalothrin produced stimulatory effect followed by relaxation on rat phrenic nerve diaphragm preparation indicating the depolarizing neuromuscular blocking activity of the drug. A transient hypotensive effect was traced, the effect revealed the peripheral cholinergic effects of the compound. Moreover, spraying healthy rabbits with lambda- cyhalothrin for 5 successive days in an effective concentration (1mg/40 ml) did not produce any changes on the blood picture, liver and kidney functions. Meanwhile the compound sprayed in double effective concentration (2mg/40ml) induced a significant decrease in erythrocytes , leucocyte counts, Hb% and P. C. V. % with a significant prolonged prothrombin time after 14,21 and 28 days of last spray. It also elicited a significant elevation of SAST, SALT, alkaline phosphatase, serum bilirubin, blood urea nitrogen, creatinine and uric acid.