Effects of Zataria Multi-Flora, Shirazi thyme, on the Severity of Premenstrual Syndrome

Premenstrual Syndrome (PMS) is a common problem in women. Zataria multiflora Boiss is a valuable plant. This herbal plant has been used in different conditions. The study was performed to investigate the effects of Zataria multiflora Boiss to control PMS symptoms. This study was a double-blinded, prospective randomized trial. The study population was the college students living in the dormitories of Isfahan University. Eighty-eight eligible students were randomly divided to intervention and control groups. Students completed the prospective record of the impact and severity of menstrual symptoms (PRISM) calendar including 30 PMS symptoms for four menstrual cycles (two cycles before, and two after the intervention). The intervention group received pearls containing 20 mg of Zataria multi-flora essence (four pearls each day) for two menstrual cycles, seven days before menstruation. The mean difference of PMS severity score between groups was analyzed with Mann-Whitney U test. The difference in frequency score of symptoms was analyzed using repeated-measure analysis of variance. Thirty-eight students in intervention and 37 students in placebo group completed the study. The groups had no significant difference regarding the severity of PMS. Both groups showed a significant improvement in PMS severity score after the intervention. The repeated-measure analysis of variance showed that the frequency of symptoms decreased significantly in the cycles, but it was not different in intervention and placebo groups. Our findings did not support the use of Zataria multiflora Boiss in premenstrual syndrome.