Aim A large amount of literature reported that Larginine-nitric oxide (L-Arg--NO) pathway involVed in the formation and progression of atherosclerosis (As)induced by hypercholesterolemia. The purpose of this study is to determine the effects of L-arginine on the atherosclerotic plaque formation.Methods New Zealand white rabbits (n=144 ) were assigned to control group, nifedipine group,isosorbide dinitrate group, L-arginine group and hypercholesterolemic group, respectively. Experiment included a 90 days' treatment and 180 days' treatment.The percentage of atherosclerotic plaque covering aortic and coronary intima was measured.Results The atherosclerotic plaque area was reduced by feeding with L-arginine at l, 1. 5 and 2 g/kg in each day at this study. While in nifedipine treated groups and in isosorbide dinitrate treated groups, the plaque area gave higher values than L-arginine treated groups, but lower than those of hypercholesterolemic groups. The effects of L-arginine on antiatherosclerosis was more significant than nifedipine and isosorbide dinitrate.Conclusion L-arginine exerts strong antiatherosclerotic effect in experimental rabbit. Nifedipine and isosorbide dinitrate has the similar effect but with a slightly weaker action.