The purpose of this study was to investigate the effect of Lycii fructus on the serum lipid in rats fed high fat diet. We compared the effects of L. fructus and L.fructus water extract both adminstered with high fat diets on rats that had previously been on high fat or standard diets. Two separate experiments were conducted for 6 weeks. respectively. In experiment I, 4 groups of rats were fed experimental diets consisting of either circled1 6 weeks of a standard diet(control), circled2 6 weeks of a high-fat diet(HHC), circled3 3 weeks of a high-fat diet followed by 3 weeks of a high-fat diet containing L. fructus(HHL) or circled4 6 weeks of a high-fat diet with L. fructus extract in place of water for the last 3 weeks (HHT). In the second set of experiments, a high-fat diet (SHC), high-fat diet containing L.fructus(SHL) or high-fat diet with L. fructus extract in place of water (SHT) were fed for 3 weeks after 3 weeks of standard diet feeding. Rats fed L. fructus diet consumed more diets than high-fat diets. THe results of experiment I showed significant decreases(p<0.05) in serum triglyceride(TB) and low density lipoprotein-cholesterol (LDL-C) levels with L. fructus feedings, but did not show andy changes in total cholesterol (TC) level. High density lipoprotein-cholesterol (HDL-C) level was increased significantly(p<0.05) with L. fructus feedings. Therefore, the ration of LDL-C to HDL-C(LDL-C/HDL-C) which is used as an atherosclerosis index was significantly (p<0.05) low, while the HDL-c/TC ration was significantly(p<0.05) high with L.fructus intake. However, no significant were found in serum cholesterols and TG levels in experimentII. The results of these experiments indicate that , regardless of the feeding from, L. fructus can be beneficial in lowering serum TG and LDL-C levels for habitual high-fat diet intakers. L.fructus also seems to be effective in elevating serum HDL-C level, theregy having beneficial effects on atherosclerosis by influencing the serum lipoprotein profile.