The effect of extracts of Pueraria tuberosa DC has been studied on the oestrous cycle of adult rats. It is found that when petroleum ether and benzene extracts are given orally to normal cyclic rats, within 3-4 days the diestrus phase is transformed into a prolonged cornified stage, which persisted till the last day of treatment indicating thereby the estrogenic nature of the extracts. The administration of crude powder and ethanolic extract also induced cornification but after the 13th day, the cornified stage changed into the diestrus stage which continued till the last day of treatment. This type of change is thought to be due to the multiple hormonal properties of the crude powder and ethanolic extract.