Three anthraquinones (1, 2 and 4), three stilbenes (5, 6 and 7) and 3,5-dihydroxybenzyl alcohol (3) were isolated from Reynoutria japonica. Their structures were identified as emodin (1), emodin-8-O-β-D-glucoside (2), 3,5-dihydroxybenzyl alcohol (3), citreorosein (4), cis-resveratrol (5),