Snuff prepared from seeds of Piptadenia peregrina, of Puerto Rico, has not been found capable of producing the intoxication attributed to it by natives or by explorers, who have described the use of these seeds under the names cohoba, parica, yopo, and nio]o. Two major constituents, bufotenine and dimethyltryptamine, did not appear capable of inducing the reputed action of the snuff, or that of Amanita muscaria. Bufotenine, up to 20 mg. intravenously, did not produce hallucinations in schizophrenic subjects, despite profound EEG changes, loss of consciousness, and intense peripheral action of serotonin character. Dimethyltryptamine had less intense physiological action but, above 20 mg. given intravenously or intramuscularly, eruption of preconscious ideations occurred. The action of both compounds was very rapid in onset and of brief duration. The compound 3- (3-dimethylaminopropyl) indole had no physical or psychological effect when given up to 70 mg. intramuscularly.