Magic Mushroom has been shown to ease cluster headaches. From Wiki:
Psilocybin has been investigated as an experimental treatment for several disorders.
In 1961, Timothy Leary and Richard Alpert ran the Harvard Psilocybin Project, carrying out a number of experiments concerning the use of psilocybin in the treatment of personality disorders and other uses in psychological counseling.[55]
A pilot study led by Francisco Moreno at the University of Arizona and supported by Multidisciplinary Association for Psychedelic Studies studied the effects of psilocybin on nine patients with obsessive-compulsive disorder (OCD).[56] The study found that psilocybin could be safely given to patients with OCD, and it was associated with substantial reductions in OCD symptoms in several of the patients.[57]
Two current studies are investigating the possibility that psilocybin can ease the psychological suffering associated with cancer. One study, led by Charles Grob, involves 12 subjects with terminal cancer being administered the hallucinogen or a placebo in two separate sessions.[58] A second study, led by Roland Griffiths at Johns Hopkins, administered psilocybin to people "with a current or past diagnosis of cancer who have some anxiety or are feeling down about their cancer".[59] Preliminary results indicate that the low doses of psilocybin can improve the mood and reduce anxiety of patients with advanced cancer, and that the effects last from two weeks to six months.[60] In 2008, the Johns Hopkins research team published guidelines for responsibly conducting medical research trials with psilocybin and other hallucinogens in humans.[61]
Additionally, psilocybin has shown promise to ease the pain caused by cluster headaches, often considered not only the most painful of all types of headaches,[62] but "one of the worst pain syndromes known to mankind."[63] In a 2006 study, 22 of 26 cluster headache patients reported successfully using psilocybin to abort the attacks, and 18 of 19 psilocybin users reported longer attack-free periods.[64]
But that little war on drugs has made any legitimate research next to impossible.