This paper presents a framework for conducting an evidence-based program of harm reduction information for ecstasy users. Findings from research on the short-term and long-term adverse effects and side effects of ecstasy are reviewed and weighed for their relevance to harm reduction programs. The review covers findings on severe adverse effects, long term effects (including potential neurotoxicity) and common unwanted acute and sub-acute effects of ecstasy. Because they are rare and not always setting or dose dependent, the author concludes that it may not be useful for harm reduction programs to focus on preventing severe adverse events. While evidence for potential neurotoxicity exists, the author argues that the effects in humans are subtle and that methodological flaws in retrospective comparative studies make study results difficult to interpret. In examining findings on potentially neuroprotective treatments, the author concludes that too little is known about the risks and benefits of these treatments in humans (as opposed to rodents) to advise their use by ecstasy users. Instead, a case is made for focusing harm reduction efforts on reducing common complaints associated with ecstasy use, such as acute somatic effects (jaw clenching, nausea) and sub-acute effects (feeling unwell or depressed, difficulty sleeping, lack of concentration). Since reducing number of tablets taken overall, average dose per use and perhaps frequency of ecstasy use would reduce these common unpleasant effects, the author suggests that harm reduction programs should focus on encouraging users to take less ecstasy. The paper also reviews and considers rate of ecstasy dependence and the usefulness of pill testing in harm reduction strategies, with encouragement given to any further research into whether pill testing reduces ecstasy related harms and ecstasy use.