Background: Premenstrual dysphoric disorder PMDD is a health difficulty that is so similar to premenstrual syndrome PMS but is more serious Many women with PMDD may also have anxiety or depression, in this way, lasting irritability or anger that may affect other people, feelings of sadness or despair, or even thoughts of suicide, feelings of tension or anxiety, panic attacks, mood swings or crying often, lack of interest in daily activities and relationships, trouble thinking or focusing, tiredness or low energy, food cravings or binge eating, trouble sleeping, feeling out of control, physical symptoms such as cramps, bloating, breast tenderness, headaches, and joint or muscle pain are some of prevalent symptoms suffer women with PMDDMethods: The present research was a randomized controlled trial. In order to control variables pain intensity and psychological distress among patients with PMDD, the participants were selected accidently from female students of Shahed University of Tehran who consulted to psychology in order to assess their premenstrual symptoms and randomly divided into two groups. Each of groups encompassed 30 women between 20 up to 35-year-old whom diagnosed by PMDD via PSST from winter 2019 to spring 2020. In this study, one group received hypnotherapy and the other group received no intervention. Results: There are significant differences between the two groups. The efficacy of the procedure of hypnotherapy in the experimental group was more than that in the control group, (sig = 0.05).Conclusion The present study findings revealed that hypnotherapy with suggestions focused on cognitive flexibility and ego strength affected pain intensity and psychological distress among females with PMDD significantly. (sig=0.05)