A phenolic compound in Foeniculum vulgare can improve human health. Foeniculum vulgar contains flavonoids, glycosides, and other constituents that are used for medicinal ailments. Trans-anethole, fenchone, and estragole essential oils are the main ingredients in F.vulgare seeds. The principle component of fennel oil, Anethole is having structural similarity with the synthetic oestrogen diethylstilboestrol which makes it an active estrogenic agent. Women with PCOS may exhibit obesity, amenorrhea, oligomenorrhea, infertility, or androgenic feature, which are characterized by the absence of ovulation and hyperandrogenism. Oligomenorrhea is a kind of irregular menstruation periods. Treatment of oligomenorrhea depends on the causes; the main cause of oligomenorrhea is polycystic ovarian syndrome (PCOS) present with 75%-85% experiencing infrequent periods. The review focuses on F. vulgare seeds as an advantageous addition to treat PCOS. Women with PCOS also have a lower level of hormone progesterone due to the absence or reduction in ovulation. Numerous phytoestrogen can be found in F. vulgare seeds, with less insulin resistance and lower blood sugar level, fennel phytoestrogen content is beneficial. It is also thought to aid in reducing the cellular imbalance that causes PCOS’s metabolic abnormalities.