Premenstrual syndrome (PMS) is a common problem which can markedly interfere with normal life. Most women have one or more emotional or physical symptoms in the premenstrual phase of the menstrual cycle. The diagnosis of PMS and premenstrual dysphoric disorder (PMDD) requires daily charting of symptoms over two or three menstrual cycles because of the variability of symptoms. Understanding the woman's problems is essential and indeed may be the most therapeutic option. The one consistent factor in randomized controlled trials on any of the PMS treatments is the very high placebo response - about 60% improvement. Selective serotonin reuptake inhibitors (SSRI) have been proven safe and effective for the treatment of PMDD. Suppression of ovulation using hormonal therapies is an alternative approach to treating PMDD when SSRIs or second-line psychotropic agents are ineffective. Herbal and vitamin supplementation, and complementary and alternative medicine have been evaluated for use in PMS/PMDD.