Hydroxycinnamic acid esters of fukiic acid and piscidic acid were isolated from a 50% ethanolic extract obtained from the rhizomes of Cimicifuga racemosa (Ranunculaceae). Besides 2-E-caffeoylfukiic acid (fukinolic acid), 2-E-feruloylfukiic acid (cimicifugic acid A), 2-E-isoferuloylfukiic acid (cimicifugic acid B), 2-E-feruloylpiscidic acid (cimicifugic acid E) and 2-E-isoferuloylpiscidic acid (cimicifugic acid F), free caffeic, ferulic and isoferulic acids were isolated. The estrogenic activity of fukinolic acid was shown by increased proliferation (126% at 5 x 10(-8) M) of an estrogen dependent MCF-7 cell system with reference to estradiol (120% at 10(-10) M).