Psilocybin or "Magic Mushrooms" have been shown, in multiple studies, that it may alleviate symptoms in many illnesses. Psilocybin is currently a Schedule I substance with "no medical value," making therapeutic use of this substance illegal. Psilocybin needs to be lowered to a Schedule II substance so patients can have access to this useful medicine and more studies can be conducted.
Psilocybin mushrooms may help cancer patients with end-of-life anxiety (1).
Psilocybin mushrooms may help alleviate painful cluster headaches. (2).
Links:
(1) http://archpsyc.jamanetwork.com/article.aspx?articleid=210962
(2) http://www.ncbi.nlm.nih.gov/pubmed/16801660