Recreational drugs that were once proscribed are now being explored as new pharmacotherapies. This topical book provides a balanced guide to new and far-reaching changes in our health system and our drug laws. Written by leading scientists, practitioners and researchers, it examines the evidence, discusses the history and context, and describes the pharmacology of recreational drugs that are being repurposed as medical treatments as well as recreational drugs that are currently being investigated. Amongst the drugs covered are psilocybin, cannabis, ketamine, MDMA, amphetamine and methylphenidate. Where known, the mechanisms of action, pharmacokinetics, putative indications, and safety and tolerability are described for each agent. Drugs used by indigenous communities for ritual purposes, currently being considered for treatment by the mainstream medical establishment, are also investigated. This is an up-to-date evidence-based resource for all people interested in the medical use of recreational drugs.