An isolated fraction with bradykinin potentiating activity, from the venom of the Egyptian scorpion Buthus occitanus, was injected i.p. in female mice (35 days old). Five days after the injection of a single sublethal dose (1 μg/g), the number of primary multilaminar and secondary follicles of the ovaries was increased. Graafian follicles were observed in 50% of the treated mice but in none of the control mice. The number and size of the uterine glands and endometrium were increased in treated mice. Concomitantly, estradiol was increased in the circulating blood, while progesterone was within the normal limits. The enhancement of cellular growth by the isolated venom fraction with bradykinin potentiating activity, could be attributed to an enhancement of some growth factor(s) responsible for stimulating the ovarian follicles and uterus.