Effects of Gastrodiae Rhizoma on serum lipids and body fat in rats fed high-fat diet supplemented with 10% (w/w) lard during 11-week experimental period were investigated. Ninety-six male rats were randomly divided into eight groups: A, negative control (lard 10%); B, positive control (lard 10%+rat chow+5 brix water extract); C, lard 10%+1% G. Rhizoma powder; D, lard 10%+5% G. Rhizoma powder; E, lard 10%+2 brix 50% ethanol extract; F, lard 10%+10 brix 50% ethanol extract; G, lard 10%+2 brix water extract; H, lard 10%+10 brix water extract. Body weight gain, although slightly higher in groups A, B, and G, did not differ significantly among dietary groups. Weights of liver, spleen, kidney, and testis were significantly higher among dietary groups. Serum total cholesterol and triglyceride concentrations were markedly higher in both control groups than group H (p<0.05). Serum HDL concentration was significantly higher in group E, and lower in group A (p<0.05). Serum LDL+VLDL concentration was significantly lower in groups E, G, and H (p<0.05). Serum testosterone level was slightly higher in groups E, D, and H. Blood glucose level was significantly higher in groups B and G, whereas lower in group H (p<0.05). Epididymal fat pad (EFP) was markedly higher in control groups than G. Rhizoma diet-fed groups (p<0.05). The results indicated that decrease in serum lipids (TC, TG, LDL+VLDL) and body fat, and increase in serum HDL and testosterone levels were higher in groups E and H extracts than groups fed G. Rhizoma powder.