This study include two experiments: the first experiment was designed to determine the effects of aniseed oil administration during the last trimester of gestation on mammary gland development and milk synthesis during lactation period. Twenty pregnant rats, at the 15th day of pregnancy, were randomly divided into two equal groups as: control group (10 animals) received tap water orally and treated (10 animals) group received aniseed oil orally (0.043 gm kg-1 B.w) during the last week of gestation, at parturition, five animals from each group were scarified and their mammary gland weight (MGwW%) was recorded. The remaining animals (5 animals group-1) were allowed to suckle their litters for the first eleventh days of lactation period. At eleventh day of lactation the litters weight gains (LWGs%) and litters stomach weight (LSwW%) was calculated. The result revealed significantly increased of the three parameters (MGwW%; LWGs%; LSwW%) in treated group as compared to control. The second experiment was designed to investigate the mechanism of action of aniseed oil. Fifteen female rats, at five weeks of age, were randomly divided into three equal groups, treated for two weeks as follow: group I ovariectomized (OA) rats received aniseed oil (0.043 gm kg-1 B.w.); group II intact (IA) rats received aniseed oil (0.043 gm kg-1 B.w.); group III sham operated (S) control rats received tap water. Four parameters; mammary gland weight%, uterine weight%, follicular stimulating hormone and lutenizing hormone (MGwW%, UwW%, FSH and LH levels) were employed. This investigation showed that MGwW% and UwW% were highest in IA, while the OA rats showed the highest levels of FSH and LH. In conclusion, aniseed oil it induces mammogenesis, lactogenesis and galactopoieses, most probably by its indirect action on the mammary glands.