We studied the effect of dietary konjac mannan on serum and liver cholesterol levels and biliary bile acid composition in hamsters. In hamsters fed a control diet supplemented with konjac mannan for 6 weeks, serum and liver cholesterol levels were decreased significantly compared to hamsters fed the control diet. Addition of konjac mannan to the cholesterol-enriched diet reduced the elevation of serum cholesterol caused by feeding cholesterol. However, the absorption of cholesterol from the intestine was not changed between the four groups. The increase in the proportion of chenodeoxycholic acid in biliary bile acids was significantly enhanced in the hamsters fed both cholesterol and konjac mannan compared to hamsters fed the control diet. The change of the bile acid composition may suggest that konjac mannan inhibits the intestinal absorption of bile acids.