The purpose of this study was designed to observe the effects of the feeding Cynanchum wilfordii extract on the improvement of the blood glucose, lipid components in the serum of dietary hyperlipidemic and streptozotocin(STZ) -induced diabetic rats(S.D. strain, ♂) fed the experimental diets for 5 weeks. Concentrations of total cholesterol, atherosclerotic index, LDL, LDL-Cholesterol, free-cholesterol. cholesteryl ester, TG, PL and blood glucose in serum were significantly higher in the cholesterol administration groups((group 2(cholesterol+water), 4(cholesterol+Cynanchum WIlfordii 3.5g% extract)) than those in the control group (group1 , basal diet+water). But the concentrations of total cholesterol. atherosclerotic index, LDL, LDL- cholesterol. free-cholesterol, cholesteryl ester, TG, PL and blood glucose in serum were remakably lower in the group 4 than those in the group 2. In the STZ(55mg/kg B.W.)-induced diabetic groups((group 3(STZ, IP.)+water), 5(STZ(IP.)+Cynanchum WIlfordii 3.5g% extract? the serum total cholesterol, atherosclerotic index, LDL, LDL-cholesterol, free-cholesterol. cholesteryl ester, TG, PL and blood glucose concentrations actions were rather lower in the group 5 than those in the group 3. In the ratio of HDL -cholesterol concentration to total cholesterol and HDL-cholesterol concentration, Cynanchum wilfordii extract administration groups were higher percentage than III the groups 2 and 3. The activities of aspartate aminotransferase(AST), alanine aminotransferase(ALT), alkaline phosphatase (ALP) and lactate dehydrogenase(LDH) in serum were rather lower in the Cynanchum wllfordii extract administration groups (group 4,5) than in the cholesterol diet group(group 2) and STZ-induced diabetic group (group 3). From the above research, the physiological activity substances in Cynanchum wllfordii were effective on the improvement of the blood glucose, lipid compositions in serum of dietary hyperlipidemic and STZ-induced diabetic rats. And particularly, physiological activity substance in Cynanchum wilfordii was more effective therapeutic regimen for the control of metabolic derangements in adult disease.