Premenstrual syndrome (PMS) is characterised by the occurrence of physical and psychological symptoms during the luteal phase of almost every menstrual cycle. These symptoms disappear at the beginning of menstruation, and a symptom-free period of at least a week ensues. Premenstrual dysphoric disorder (PMDD) is a variation of PMS, with predominantly psychological symptoms. The aetiology of PMD and PMDD is not known. A possible explanation however is an abnormal, stronger reaction to physiologically normal hormonal fluctuations. Diagnosing PMS and PMDD requires prospective daily monitoring of symptoms over at least two menstrual cycles. No effective medication for the treatment of PMS has been registered in the Netherlands. In randomized placebo-controlled trials selective serotonin reuptake inhibitors and oral contraceptives containing drosperinone have been found to have a positive effect on the physical and psychological symptoms of PMS and PMDD.