This study done to investigate the hypocholesterolemic effect of ow dietary fiber in a high cholesterol diet in aspect of cholesterol absorption and excretion using Sprague Dawley rats. After feeding diets containing 0.5% cholesterol and 5% tangerine pulp, sea tangle or prickly pear cactus for four weeks, we measured the levels of plasma and liver cholesterol and triglyceride, fecal neutral sterols and fecal radioactivity after ingestion 14(sup)C-cholesterol. We also examined platelet aggregation and histological change in liver tissues in association of hypercholesterolemia. The liver to body weight ratio was significantly(p<0.01) lower in rats fed prickly pear cactus than in other groups. The levels of plasma total cholesterol, LDL-cholesterol and triglyceride were decreased significantly(p<0.01) in the prickly pear cactus group compared with the control, while there was no difference in the liver levels of total cholesterol and triglyceride among groups. Fecal corprostanol and cholesterol were significantly(p<0.01) higher groups of control and prickly pear cactus compared to the other two groups. Radioisotope excretion after ingestion of 14(sup)C-cholesterol was higher in the control group than in tangerine pulp group or sea tangle group, with the highest in prickly pear group. Radioisotope excretion was the highest during the 2nd and 3rd days in all groups. Hematocrit and platelet aggregation were decreased in all fiber groups compared to the control, but not statistically different. Microscopic examination showed that cholesterol diet cause a fat accumulation in the liver and prickly pear cactus decreased the fat accumulation. Result indicates that prickly pear cactus has hypocholesterolemic effect by decreasing absorption and increasing excretion of cholesterol, thereby protective effect on fatty liver. Control group fed diet containing high cholesterol and low fiber seems to have a self control system in cholesterol absorption and excretion preventing hypercholesterolemia. (Korean J Nutrition 34(2) : 141-149, 2001)