Claudio Naranjo’s experience with psychoactive substances is even more impressive than his work with new psychotherapeutic techniques. Over the years, he has experimented with more than thirty compoundsmostly psychedelics and amphetamine derivatives — as adjuncts to psychotherapy. He made a special canoe journey up the Amazon River to connect with South American Indians and study their use of ayahuasca or yage1, a vision-inducing drink made from a psychoactive jungle vine (Banisteriopsis caapi) mixed with various other psychoactive plants. He brought back samples of the ingredients of this psychedelic brew and published the first scientific description of the effects of its principal active alkaloids. Although he has worked with all the classic psychedelics, his unique contribution is in the area of new or less known psychoactive substances.