Most hallucinogens and cannabinoids fall into Federal Controlled Substances schedule 1, meaning they cannot be prescribed by practitioners, allegedly have no accepted medical use, and have a high abuse potential. The legal and regulatory status has inhibited clinical research on these substances such that there are no blinded studies from which to assess true efficacy. Despite such classification, hallucinogens and cannabinoids are used by patients with headache on occasion. Cannabinoids in particular have a long history of use for headache and migraine before prohibition and are still used by patients as a migraine abortive. Hallucinogens are being increasing used by cluster headache patients outside of physician recommendation mainly to abort a cluster period and to maintain quiescence for which there is considerable anecdotal success.