Mechanistically, B. vulgatus is involved in bile acid metabolism and leads to decreased levels of GDCA and TUDCA in women with PCOS, which inhibits the secretion of interleukin 22 from intestinal innate lymphoid cell 3 (ILC3), thus contributing to the development of ovarian dysfunction and metabolic disorders in PCOS [5, 6]. This evidence concerns the gene IL22 and polycystic ovary syndrome.