Aim Polycystic ovary syndrome (PCOS) is a complex disorder with gynecological, metabolic and carcinogenic effects. Increased intestinal permeability is related with obesity, insulin resistance, type 1 and 2 diabetes mellitus. The existence of such a relationship between PCOS and intestinal permeability has come to an end. Zonulin can change intestinal permeability, and this effect is reversible. We studied the relation between zonulin and the hormonal and metabolic parameters of PCOS.