Background and Objective: Herbal products consumption is increased worldwide. This study was done to compare the effect of Evening Primrose, Vitex agnus and vitamin E on premenstrual syndrome. Methods: In this clinical trials study, 210 women with premenstrual syndrome were randomly divided eqaly into Evening Primrose (500 mg, 3 times per day), Vitex agnus (40 mg/day) and vitamin E (400 Iu/day) groups. The subjects were received the thraputic regiment for 2 months. Severity of premenstrual syndrome was recorded for each subject using DSR Dickerson questinare, perior and at the end of intervention. Results: After intervention, severity of premenstrual syndrome was reduced in Evening Primrose group (60.58±30.6 to 34.09±19.81), Vitex agnus (61.23±30.54 to 25.25±17.78) and the vitamin E group, (61.24±32.04 to 54.9±19.24). Severity of premenstrual syndrome were reduced in the Evening Primrose and Vitex agnus groups in compared to vitamin E group (P<0.05). Severity of premenstrual syndrome were reduced in Vitex agnus in comparision with Evening Primrose (P<0.05). Conclusion: Vitex agnus, Evening Primrose and vitamin E can reduce severity of premenstrual syndrome, but therapeutic effect of Vitex agnus is more than Evening Primrose and vitamin E.