After presenting a brief history of MDMA and illicit ecstasy use, the authors critique common assertions made about the risks of ecstasy use, particularly claims relating to the neurotoxic potential of ecstasy. This paper was written for an audience of psychologists, and informed non-psychologists. The authors address issues of ecstasy content and purity, actual frequency of ecstasy-related deaths, the occurrence of severe adverse effects, and findings from animal and human studies. The authors note that the purity and contents of illicit ecstasy vary widely, and that ecstasy deaths are relatively rare. In examining findings of MDMA neurotoxicity in non-human animals, the authors raise questions about the doses of MDMA used in these studies, and while they acknowledge that some studies have found functional differences between MDMA-treated and saline-treated animals, many other studies have failed to find such differences. Several methodological flaws of retrospective human studies are noted, including sampling biases, lack of verification for self-reported drug use, and the issue of polydrug use in ecstasy users. The authors argue that lifestyle factors, such as disrupted circadian rhythms, might be at least partly responsible for differences in cognitive function found between ecstasy users and non-users. The authors do not address recent findings indicating reduced axonal transport in rat synaptosomes (Callahan et al. 2001), a strong indicator of injury to serotonergic neurons. Along with another recent critique of studies in ecstasy users (Kish 2002), this paper suggests that it would be premature to draw firm conclusions about MDMA neurotoxicity in humans on the basis of currently available information. Morgan (Morgan 2002), Croft (Croft 2002) and Parrott (Parrott 2002) commented upon and critiqued this paper, and the authors replied to each critique (Cole et al. 2002b), with all commentaries and the authorsŐ reply published alongside the original paper.