The originally published report (1) presented results from multiple studies performed in our laboratory over a span of approximately 2 years demonstrating that a novel systemic dose regimen of what we believed was MDMA produced severe dopamine neurotoxicity in two species of nonhuman primates, in addition to the previously reported serotonin neurotoxicity (3–6). Subsequent to the publication of those findings, we were unable to extend the dopamine neurotoxicity to orally administered doses. Multiple subsequent attempts to reproduce the original findings with systemically administered doses of MDMA identical to those used in the original study were also unsuccessful, under a variety of laboratory conditions.