This study was conducted to investigate the antioxidative effects of Paeonia lactiftora Pall. (PL) seed extracts and Forsythia viridissima Lindl. (FVL) extracts on the antioxidative defense system and lipid peroxidation in the erythrocytes of rats fed a high-cholesterol diet. Sprague-Dawley male rats weighing 100 10 g were randomly assigned to nine experimental groups and fed 0.5 % cholesterol. The HC group did not receive any supplement, while the MP group was supplemented with 0.1 % methanol extract of PL seed, the MP2 group with 0.2 % methanol extract of PL seed, the EP1 group with 0.05 % ether-soluble fraction of PL seed, the EP2 group with 0.1 % ether-soluble fraction of PL seed, the MS1 group with 0.05 % methanol extract of FVL, the MS2 group with 0.1 % methanol extract of FVL, the ES group with 0.025% ethyl acetate-soluble fraction of FVL, and the ES2 group with 0.05 % ethyl acetate-soluble fraction of FVL. The experimental diets were fed ad libitum for 3 weeks. The erythrocyte SOD activity in the EP1 and EP2 groups increased 38% and 59%, respectively, when compared with the HC group, while the erythrocyte GSHpx activity in the EP1, EP2, and ES2 groups increased 30%, 31 %, and 29%, respectively, when compared with the HC group. The level of erythrocyte TBARS was significantly lower in the MP2, EP1, and EP2 groups than in the HC group, yet the level of serum TBARS was significantly lower in the all supplemented groups than in the HC group. The level of serum HDL- TBARS was significantly lower in the EP1 and EP2 groups than in the HC group, while the level of serum LDL- TBARS was significantly lower in the all the supplemented groups than in the HC group. Accordingly, the results indicated that the PL seed extracts and FVL extracts reduced oxidative damage by activating the antioxidative defense system in the erythrocytes of rats fed a high-cholesterol diet.