As a methanol extract of the rhizome of Rhodiola rosea inhibits the activity of lipase in isolated mouse plasma in vitro and in the mouse gastrointestinal tube in vivo, the active components in this plant were investigated. After fractionation and separation processes, rhodionin and rhodiosin were isolated as active ingredients. Their IC50 values were 0.093 mM and 0.133 mM in vitro, respectively. Both compounds significantly suppressed the elevation of the postprandial blood triglyceride level, e.g., by 45.6 % (150 mg/kg, 60 min after oral administration) and 57.6 % (200 mg/kg, 180 min after oral administration), respectively. Consequently, we anticipate the application of this plant and its constituents to the treatment of lifestyle-related diseases such as hyperlipidemia and exogeneous obesity and to health foods.