Premenstrual symptoms have been recognised since Hippocrates in 370AD when menstrual bleeding was thought to purge melancholic and choleric humors [1]. They occur to some degree in most women which has led to hypotheses about past evolutionary benefit. One theory is that for our hunter-gatherer ancestors PMDs would have conferred a selective advantage; by encouraging males to seek out a more receptive (and possibly less aggressive) ovulating female the likelihood of productive mating would have been increased [2]. But what was once perhaps adaptive is now clearly maladaptive for modern women. Severe premenstrual disorders, including PMDD, which is the main focus of this review, have an enormous impact women’s physical, psychological, social and economic wellbeing. Despite an explosion of research into PMDs many women are still not being diagnosed accurately and so are not accessing the support and treatment they need.