Malathion is an organophosphorous compound widely used as pesticide, mostly in spray form. The present project was designed to study the effect of Malathion on lipid profile and inhibition of cholinesterase activity in rabbits. The experimental rabbits were kept at the animal shed of Department of Pharmacology and Toxicology and were divided into five groups A, B, C, D, and E, each comprising of five animals. All the animals of each groups were shaved from their dorsal side for the application of Malathion. The animals of group A were treated with Malathion 50 mg / kg body weight, dermally. Group B was treated with 100mg of Malathion per kg B.W., dermally. Rabbits in group C were treated with Malathion at the rate of 200mg! kg B.W. Group D was treated with 400mg/kg B.W., dermally. The application of Malathion was repeated on Day 1, Day 3, Day 5 and Day 7 of the experiment. Group E was as control. Blood samples were collected from each animal separately before and after the experiment from their marginal ear veins. Serum was separated from the blood samples and was further analyzed for cholinesterase activity and lipid profile by spectro photometric method. Specified Randox kits were used for this purpose. Data collected from the experiment showed that Malathion inhibits the activity of cholinesterase enzyme. Also Malathion influences the lipid profile. In group A which was treated with Malathion 50mg/kg, the total cholesterol was increased up to 27.11%, high density lipoprotein (HDL) were increased up to 22.40%, low density lipoprotein were increased up to 175.44% and triglycerides (TGs) were decreased by 14.42%. In group B which was treated with Malathion 100mg/kg, total cholesterol was increased up to 34.46%, HDL increased up to 35.40%, LDL increased up to 183.09% while TGs were decreased by 14.02%. In group C which was treated with Malathion 200mg/kg, total cholesterol was increased up to 31.46%, HDL were increased up to
42.10%, LDL were increased up to 137.44% and TGs were decreased by 15.44%. While in group D which was treated with Malathion 400mg/kg, total cholesterol was increased up to 23.46%, HDL were increased up to 45.76%, LDL were increased up to 82.37% and TGs were decreased up to 14.95%.Activity of cholinesterase was decreased up to 82.74%, 91.59%, 89.63% and 86.64% in different groups like group A, B, C and D respectively. All the results were compared with the values of control group E. All the data obtained from these experiments was analyzed statistically.