The aim of this double-blind study was to investigate the effects of Berberis vulgaris fruit extract, saffron (Crocus Sativus L.) and placebo on metabolic syndrome. The population in this third-phase clinical trial included all patients referred to cardiac outpatient clinic of Birjand University of Medical Sciences. A total of 90 patients who were diagnosed with metabolic syndrome, aged between 30 and 60 years, and were willing to participate in the study were randomly selected and allocated into three groups through simple randomization method. A total of 30 patients were allocated into the saffron group, 30 into barberry group, and 30 into the placebo group. The saffron group received on a daily basis a tablet of 100 mg of crocin (constituent of saffron) on a daily basis for three weeks. The barberry group received three 550 mg tablets of Berberis vulgaris fruit extract (an aqueous extract) per day for three weeks. The placebo group received starch tablets, similar in appearance to tablets in other groups, one per day for three weeks. Metabolic syndrome variables, i.e., body mass index, blood pressure, fat distribution pattern, fasting blood sugar, serum lipid level, triglycerid, total cholesterol, and low and high density lipoprotein were measured at baseline and at the end of interventions.