Salvinorin A, a neoclerodane diterpene, is the most potent naturally occurring hallucinogen known and rivals the synthetic hallucinogen lysergic acid diethylamide in potency. Recently, the molecular target of salvinorin A was identified as the kappa opioid receptor (KOR). Salvinorin A represents the only known non-nitrogenous KOR selective agonist. Based on the selectivity of salvinorin A for the KOR, this receptor represents a potential molecular target for the development of drugs to treat disorders characterized by alterations in perception, including schizophrenia, Alzheimer's disease and bipolar disorder.