Lysergic acid diethylamide (LSD) and psilocybin are the prototypic indolealkylamine hallucinogens, which also include N,Ndimethyltryptamine and bufotenin. Aside from great differences in potency (1 Ilg LSD equals 225 Ilg psilocybin equals 5 mg mescaline), the clinical syndromes produced by these three drugs are virtually identical. Somatic symptoms include dizziness, weakness, tremors, nausea, drowsiness, paresthesia, and blurred vision. Perceptual changes include altered shapes and colors, difficulty in focusing on objects, sharpened sense of hearing and, rarely, synesthesias. Psychic manifestations include alterations in mood, tension and, rarely, hallucinations. The usual doses, in terms of LSD, to produce such effects range from 50 to 200 ug. No fatal overdoses have been recorded. The usual duration of drug effect is about 6 to 8 hours, or longer with higher doses. It is conceivable that MDA is not truly a hallucinogen. Substitution of the aromatic portion of the molecule at the 3 and 4-positions is usually not adequate for producing hallucinogenic effects. Thus, the contention that MDA is not truly a hallucinogen but more closely related to amphetamine may be correct. Whether MDMA will, despite its evident hazards, prove to be the panacea for psychotherapy claimed by its adherents remains to be seen. The present claims are exactly the same as those made by many of the same persons about LSD 20 years ago.