Isolation, 'H-NMR and 13C-NMR studies on rhazimal and strictamine are described. The proton assignments have been made on the basis of two-dimensional NMR measurements (COSY-45) and homo-decoupling experiments. n-Butanol fraction of aerial parts of Achyranthes aspera Linn. prevented pregnancy in adult female rats when administered orally at 75 mg/kg dose on days 1—5 postcoitum, but was ineffective in hamsters upto 300 mg/kg dose. In ovanectomized immature female rats, the extract exhibited potent estrogenic activity at the contraceptive dose but was devoid of any antiestrogenic activity. 100% uterine weight gain was achieved at 1/ 15th of the contraceptive dose. Significant uterotrophic effect was discerned even at 1/ 20th of the contraceptive dose. Taking 100% increase in uterine weight as the parameter, estrogenic activity of the extract was found to be 1/2750 that of ethynylestradiol.