LAUSR

Abstract Background Polycystic ovarian syndrome (PCOS) is the most common cause of ovulatory infertility with an endocrine origin. An alternative therapy for PCOS is complementary medicine (CM), with herbal medicine becoming the most popular during the past ten years. The fennel plant (Foeniculum Vulgare Mill) belongs to the flowering plant of the fennel Apiaceae family. It is a medicinal plant that is commonly recommended by practitioners of Iranian traditional medicine for ovarian or unknown infertility in women because it has an estrogenic effect. The effects of fennel (FOEVU: Foeniculum vulgare Mill essence of fennel seeds) on PCOS has yet to be investigated. Therefore, the main objective of our study was to investigate and evaluate the effects of fennel essential oil capsules on PCOS symptoms. Subjects and methods This study was a double-blinded, randomized controlled study. Our subjects were thirty female students who were selected from the age range of 20–35 and met the Rotterdam diagnostic criteria for PCOS. The subjects were randomly assigned to two groups: fennel (study) and placebo (control). The ultrasonography assessments, body mass index, biochemical, and hirsutism variables were measured individually before and after three months usage of the fennel and placebo as our main outcome measurements. The comparison between the quantitative data obtained for the two studied groups was carried out using the Man-Whitney and chi-square tests. Results The comparison of menstruation cycle, hirsutism, BMI, biochemical, and ultrasonography measurements revealed that the interventions did not cause significant differences in the two groups, except in the dehydroepiandrosterone sulphate (DHEAS) and both ovarian follicles number (p  Conclusion Fennel was not effective in alleviating the ovarian cyst symptoms in polycystic women but since the sample size calculation in our small study was based on very large effect sizes, the study might not be powered enough to detect smaller effects.