Post-traumatic stress disorder (PTSD) is a disabling condition that afflicts 1-10% of the general population, with twice as high lifetime prevalence for women than men. Treatments exist, but none have proven reliable and consistent efficacy. A large minority of patients remain treatment-resistant despite undergoing several different types of treatment over extended periods of time. Recently completed studies in the U.S. and in Switzerland have demonstrated the potential of 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy for treatment-resistant PTSD. One of the major problems of treating PTSD is the patients’ fear state and inability to form a therapeutic alliance. Both these issues can be facilitated through administration of MDMA; the psychological effects - such as heightened empathy, increased openness and diminished anxiety – seem well-suited for therapeutic purposes. The rationale behind treating PTSD with MDMA has been indicated in neuroimaging studies; MDMA affects some of the neural structures altered in patients with PTSD, most notably the amygdala and the ventromedial prefrontal cortex. Using the Schedule 1 substance MDMA for this purpose is however controversial; animal studies have indicated that MDMA is neurotoxic, although no adverse effects on humans related to incidental use of MDMA in a controlled setting have been found. In conclusion, the data support that MDMA may be an efficient tool for treating PTSD, as well as safe and effective to use in a clinical context.