Given the importance ofunderstanding the action of herbal medicines at genes level, in the present study, we investigated the effect of Vitex agnus-castus fruit ethanolic extract on the expression of hypothalamic KISS-1 gene in a rat model of PCOS; Our assumption was that Vitagnus has a positive effect on regulating the levels of sex hormones to relieve issues associated with related to PCOS by regulating kisspeptin neurons activity. The gene discussed is KISS1; the disease is polycystic ovary syndrome.