This narrative review describes the provenance and chemical composition of Vitex agnus-castus, as well as the currently available knowledge concerning its action. To search the related articles, Cochrane Library, PubMed, Web of Science, SCOPUS databases between the years 1995 and 2024, and the keywords “Vitex,” “review,” “fertility,” “ovarian” and “mechanisms” were used in various combinations. The data listed in this review demonstrate that Vitex agnus-castus and its constituents (isoflavones and essential oils) affect a number of physiological actions via multiple extra- and intracellular mechanisms of action. This makes it an efficient drug in both traditional and modern medicine for the treatment of a number of illnesses. The main described target of Vitex agnus-castus is female reproduction. It can up-regulate ovarian cycle and fecundity via a wide spectrum of mediators from hypothalamic, pituitary and ovarian hormones up to intracellular regulators of proliferation, apoptosis, oxidation and dopamine receptors. These effects determine its potential action as protector and medicine against a number of female reproductive disorders and reproduction-related health problems including menstrual disorders, premenstrual syndrome, cyclic mastalgia, corpus luteum insufficiency, abnormal production of progesterone and prolactin, low fertility and infertility, hyperandrogenism and polycystic ovarian syndrome. Nevertheless, further high-quality studies are needed to firmly establish the biological and clinical efficacy of this plant.