Background: This study aims to investigate the effects of Salvia officinalis on the severity of the premenstrual syndrome (PMS). Methods: This was a triple-blinded randomized clinical trial on 90 college students in Tehran, Iran. The participants were randomly divided into 2 groups who were treated with 500-mg Salvia officinalis capsules or placebo once a day for 2 consecutive months. Data were collected using a questionnaire and a daily form for recording symptoms of PMS. Results: The mean decreases in severity of the symptoms in the Salvia officinalis extract-treated group during the first and second months after treatment were 19.84% and 23.42%, respectively. The comparison of the PMS physical and psychological symptoms demonstrated a decrease following treatment in both groups, with more remarkable reduction in the Salvia officinalis group (p < 0.001). Conclusion: Salvia officinalis is an effective alternative agent to reduce the severity of psychological and physical symptoms of PMS.