This study was conducted to identify the effects of Cynanchi Wilfordii Radix and Polygoni Multiflori Radix liquors on lipid peroxidation and antioxidant activity in rats. Male Sprague-Dawley rats were placed on a liquid diet for six weeks. The rats were assigned to one of four experimental groups according to the following liquid diet types: a normal liquid diet (C), the soju liquid diet (A), a Cynanchi Wilfordii Radix liquor diet (WA) and a Polygoni Multiflori Radix liquor diet (RA). Except group C, alcohol contributed 12% of the total calories consumed by the rats. The results of MDA level and antioxidant activity of serum and brain tissue of rats were as follows. The serum and brain MDA levels of WA and RA groups could be lowered to the group C level. The nitric oxide (NO) level of the brain tissue of the RA group was lowest in all the groups. Serum superoxide dismutase (SOD) activity in the A and WA groups were significantly elevated. Serum catalase activity was significantly higher in the WA group than it was in groups C and A. Glutathione peroxidase (GSH-Px) activity in brain tissue was significantly elevated in the WA and RA groups relative to group A. Among all the experimental groups, the total serum antioxidant capacity in group A was lowest. This indicated the soju liquid diet led to oxidative damage in these rats. In contrast, the Cynanchi Wilfordii Radix and Polygoni Multiflori Radix liquor diets effectively inhibited lipid peroxidation and NO production.