AbstractA tetranor‐cycloartane glycoside and two 9,19‐cycloartane glycosides were isolated from the EtOAc‐soluble fraction of the rhizome of Cimicifuga foetida. The structures of the compounds were determined to be cimilactone A (1), 25‐O‐acetylcimigenol 3‐O‐β‐d‐xylopyranoside (2) and cimigenol 3‐O‐α‐l‐arabinopyranoside (3), respectively, using spectroscopic analysis. The three compounds were examined for their anticomplement activity against the classical pathway of the complement system. Compound 1 showed significant anticomplement activity with an IC50 value of 28.6 µm, whereas compounds 2 and 3 were inactive. Copyright © 2006 John Wiley & Sons, Ltd.