Study aim: *A) General Objective: To determine the efficacy of a combination product based on Chasteberry (Vitex agnus-castus*) compared to Dydrogesterone on oligomenorrhea caused by Polycystic Ovary Syndrome (PCOS) Design: Patients will be randomly assigned to two groups (control and intervention) using block randomization in blocks of four. Randomization will be performed using a random allocation list generated by Excel. The study will be conducted in a triple-blind manner (blinding the patient, the primary investigator, and the statistical analyst). To ensure blinding, Dydrogesterone and the herbal medication will be randomly assigned codes A and B; these codes will only be revealed after the statistical analysis is completed to prevent performance and information bias. The control group will receive 10 mg of Dydrogesterone, while the intervention group will receive a herbal capsule formulated from Chasteberry (including Vitex agnus-castus* seeds, Daucus carota seeds, and Mentha pulegium leaves). Furthermore, Dr. Samira Eghbali, a faculty member at the School of Pharmacy, Birjand University of Medical Sciences, is designated to handle the coding of medications and patients to maintain the triple-blind integrity of the study Settings and conduct: Gynecology clinics at Valiasr Hospital and Rouyesh Infertility Center, Birjand, during 2026-2027. Participants/Inclusion and exclusion criteria: Women18-45age with pco Intervention groups: chemical drog and herbal drog Main outcome variables: Incidence of menstrual bleeding and regularization of cycles.