Pancreatic lipase-inhibitory activity of the rhizome of Rhei Rhizoma and its antihyperlipidemic activity were measured. Rhei Rhizoma inhibited pancreatic lipase with $IC_{50}$ value of 6.5 mg/ml (triolein as a substrate). Rhei Rhizoma significantly inhibited serum TG level in corn oil feeding-induced mice, and serum TG and cholesterol in Triton WR-1339-induced hyperlipidemic mice. However, Rhei Rhizoma did not show the hypolipidemic activity in high cholesterol diet-induced hyperlipidemic mice. When in vitro pancreatic lipase-inhibitory and in vivo antihyperlipidemic activities of Whangryunhaedoktang (WT) and Chunghyuldan (CD), which is consisted of ingredients of WT and Rhei Rhizoma, were measured, CD exhibited more potent inhibitory activities than WT. Therefore these results suggest that antihyperlipidemic activity of Rhei Rhizoma and CD may be more or less originated from the inhibition of pancreatic lipase.