The ethanolic extract of FERULA JAESCHKEANA Vatke as well as its hexane, benzene and chloroform soluble fractions prevented pregnancy in adult female rats when administered orally on days 1-5 POSTCOITUM. Chromatography of these combined fractions, whose TLC pattern was similar, yielded the active compound ferujol. Single oral administration of ferujol on days 1, 2 or 3 POSTCOITUM at 0.6 mg/kg dose prevented pregnancy in rats. None of the fractions nor ferujol, however, exhibited any contraceptive efficacy in hamsters. In ovariectomized immature female rats, ferujol showed potent estrogenic activity at the contraceptive dose, but was devoid of any antiestrogenic activity. Significant uterotrophic effect was discerned even at 1/40th of the contraceptive dose of the compound. Taking 100% increase in uterine weight as the parameter, ferujol was found to be about 10 times less estrogenic than ethynylestradiol. In addition, ferujol induced implantation of blastocysts in mice undergoing experimentally induced delayed implantation, confirming its frank estrogenic activity.