E for Ecstasy by Nicholas Saunders
Appendix 1: Reference Section

12 The Background Chemistry of MDMA, by Alexander Shulgin, from Journal of Psychoactive Drugs, Vol. 18/4 1986

According to this paper, MDMA is less toxic than MDA but more so than mescaline. The lethal dose is between 20 and 100 mg per kilo of body weight depending on the species taking it. With mice, it is 5 times more toxic given in crowded conditions than in isolation. [20mg/kg is equivalent to an adult human taking about 12 Es.]

Shulgin says that research implies some functional role of serotonin in the mechanism of MDMA and that there is evidence that MDA and MDMA have different mechanisms of action. For example there is no cross-tolerance between the two drugs.

He notes that two studies commissioned by the US government on the abuse potential of MDMA showed that monkeys that had been trained to self-administer cocaine tended to "reinforce themselves with MDMA", indicating that MDMA has potential for abuse by hard-drug addicts. But he also points out that press reports and anti-drug usage material often [falsely] attribute to MDMA the effects and dangers of other drugs and that reporters repeat each others' mistakes.