Aim To investigate the effects and mechanisms of Gypenosides on the atherosclerotic plaque formation in rabbit with hypercholesterolemia.Methods 23 male New Zealand white rabbits were assigned to four groups:5 rabbits in control group were fed with a normal diet;8 rabbits in hyperc-holesterolemic group were fed with 1% cholesterol diet for 9 weeks;In gypenosides and vitamine E (Vit E)treat groups,5 weeks after fed with 1% cholesterol di-et the animals were fed with 1% cholesterol diet con-taining gypenosides or Vit E for another 4 Weeks.Sudan IV stain was used to show the relative area ofatherosclerotic plaque.Lipid peroxides of aorta were estimated by the thiobarbituric acid method.Nitrite,the matabolic product of nitric oxide,was determined according to a modified Griess' method.The Ca2+.K+ and Na+ content of aorta were measured in means of atom absorption.Results Gypenosides treatment (120 mg/d,4weeks)inhibited formation of atherosclerotic plaque as shown by 37% reduction of plaque areas comparing to 1% cholesterol treatment along.Gypenosides also decreased lipoperoxidation of aorta by 33%.In addi-tion,gypenosides protected nitric oxide release of aorta against hypercholesterolemia damage and reduced Ca2+content of aorta by 50%.However,both hyperc-holesterolemia and gypenosides had no influence on K+and Na+ content of aorta.Vit E showed the same ef-fect as gypenosides did.Conclusion Gypenosides atlenuates the formatiom of atherosclerotic plague and lipoperoxidation of aorta induced by hypercholesterolemin in rabbit.The mecha-nisms of antiatherogenic effects of gypenosides might include its protection on nitric oxide and its inhibition on calcium overload.