Polycystic ovary syndrome (PCOS) is one of the common endocrinal disorders affecting women in reproductive age group [1]. It has a negative reproductive, cosmetic and metabolic effects. PCOS is a combination of ovulatory dysfunction with clinical and/ or biochemical evidence of hyperandrogenism [2]. PCOS was first described by Stein Leventhal in 1935 [3]. It was a merely descriptive diagnosis to infertile women with bilateral enlarged ovaries. The concern about clinical and biochemical status was first implemented to the definition by National Institute of Health in 1990 [2]. In 2003, Rotterdam criteria in diagnosis of PCOS has been introduced, which includes an ultrasound picture of polycystic ovary, in women with oligo/hypomenorrhea and/or hyperandrogenism [4]. The syndrome was simply defined later in 2009 by Androgen Excess and PCOS Society (AE-PCOS), as a syndrome of hyperandrogenism in women with ovulatory dysfunction or polycystic ovarian morphology in ultrasound [1]. Due to heterogeneity of the symptoms, the prevalence of PCOS shows high variable range, it ranges from 2.2% to 26.7% [5]. Increased insulin resistance, compensatory hyperinsulinemia and hyperandrogenemia constitute a corner stone in the pathogenesis of PCOS [4], so metformin remains for decades the drug of choice for treating this condition. The effect of metformin in reversal of symptoms have been confirmed in both obese and lean PCOS patients [6]. The medical application of Cinnamon extract has been issued before. Its effect in improving insulin resistance and lowering fasting blood glucose in rats and human has been published. This in turn, gave a hope to use Cinnamon in treatment of metabolic syndrome and polycystic ovary syndrome [7,8]. 1.1. The aim of the study This study aimed to evaluate the added value of cinnamon to metformin in controlling symptoms of polycystic ovary syndrome. 2. Patients and methods This randomized controlled trial was conducted by the Obstetrics and Gynecology department of the Saudi German Hospital, Madinah-KSA, during the period from September 2015 to May 2017. All patients gave a written informed consent before participation. The study included 175 patients who met the following inclusion criteria: female age 18–35 years, overweight (Body mass index (BMI) 25–29.9 kg/m2) and obese patients (BMI
30 kg/m2) with PCOS attending the Obstetrics and Gynaecology clinic seeking advice for oligomenorrhea or amenorrhea with or without hirsutism. Oligomenorrhea was described as cycle interval of more than 35 days but less than six months. Amenorrhea was described as no menstruation for more than six months. PCOS was diagnosed according to the Rotterdam ESHRE/ASRM Consensus workshop, 2004 [9]. Patients at increased risk of developing diabetes (prediabetes) defined according to the American Diabetes Association 2014 [10] were included. Those patients had impaired fasting glucose (IFG) [fasting plasma glucose (FPG) levels 100–125 mg/dL], or impaired glucose tolerance (IGT) [2-h values in the oral glucose tolerance test (OGTT) of 140–199 mg/dL]. Patients with Glycosylated Haemoglobin A1C levels between 5.7 and 6.4% who were considered at very high risk of developing diabetes according to the International Expert Committee 2009, were included [11]. Exclusion criteria were: lean or average weight (BMI < 25 kg/m2) PCOS, patients suffering from any other metabolic diseases, history of receiving any drug known to affect carbohydrate metabolism or any hormonal medication 3 months prior to commencement of the study and inability to attend for regular follow ups. Well known and recently discovered diabetic patients were excluded from the study. Diabetes was defined according to the American Diabetes Association 2014 [10] Hyperprolactinemia and thyroid diseases were treated before participating in the study