This study was conducted to investigate the antioxidative effects of Paeonia lactiflora (PL) seeds on antioxidative defense system and lipid peroxidation of liver in rats fed high-cholesterol diet. Sprague-Dawley male rats weighing 100 $pm$10g were randomly assigned into five experimental groups fed 0.5% cholesterol ; HC group which was not supplemented PL seeds extract, 0.1% methanol extract diet group (MP1 group), 0.2% methanol extract diet group (MP2 group), 0.05% ether-souble fraction diet group (EP1 group) and 0.1 % ether-souble fraction diet group (EP2 group). Experimental diets were fed ad libitum to the rats for 3 weeks. The activity of hepatic superoxide dismutase (SOD) was not significantly different among all the high cholesterol diet groups. The hepatic glutathione peroxidase (GSHpx) activity in MP2 group was increased to 27% compared to HC group. The activity of hepatic catalase (CAT) was not significantly different among the all high cholesterol diet groups. The hepatic glutathione S-transferase (GST) activity in the EP1 and EP2 groups were increased to 12% and 13%, respectively, as compared to HC group. The levels of hepatic TBARS in the MP1, MP2, EP1 and EP2 groups were reduced by 18%, 21%, 20% and 23%, respectively, as compared with HC group. The contents of lipofuscin in liver was not significantly different among all the experimental groups. The results indicated that PL seeds extract may be reduced oxidative damage by activating antioxidative defense system of hepatic in rats fed high-cholesterol diets. (Korean J Nutrition 36(8): 793∼800, 2003)