The efficacy of Liposem, a polyherbal formulation, as an antioxidant and hypolipidaemic drug was evaluated in diet induced hyperlipidaemia in rats. The methanolic extract of Liposem was found to scavenge hydroxyl and superoxide free radicals, the IC50 required being 70.5 and 45.0 microg respectively. The lipid peroxidation in rat liver homogenate induced by Fe2+ ascorbate system was also found inhibited (50%) by 273.5 microg of the extract. The hypolipidaemic effect was assessed by serum lipid profile in dietary hyperlipidaemic rats and found to have decreased dose dependently in all the four different concentrations of administration (100, 200, 300 and 400 mg/kg body wt). Liposem significantly raised high-density lipoprotein (HDL) cholesterol and the HDL/low density lipoprotein + very low-density lipoprotein (VLDL+LDL) ratio. The atherogenic index and the reduction in body weight were significant, indicating the effectiveness against hyperlipidaemia and obesity. These results reveal the therapeutic potential of Liposem against the vascular intimal damage and diet induced hyperlipidaemia leading to the various types of cardio vascular diseases.