Abstract: AIM To study the anthraquinone constituents of the stem of Cassia siamea. METHODS The compounds were isolated by chromatography on silica gel, MHPLC, and identified on the basis of spectral analysis including IR, EI-MS, FAB-MS, ¹HNMR,¹³CNMR and DEPT. RESULTS Three compounds were isolated and identified as: chrysophanol (I), chrysophanol-1-O-β-D-glucopyranoside (II) and 1-(β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl) oxy-8-hydroxyl-3-methy-9,10-anthraquinone (III). CONCLUSION III is a new compound, II was obtained from this plant for the first time.