Proceedings of a Symposium held in San Francisco, California, January 28-30, 1967. The use of plants or their extracts for medicinal or religious ceremonial purposes is very old - practically as old as the human race. The information about the use of plants as psychotropic agents by man is probably found in the Bible. The apple that Adam ate (whatever the variety) could be considered as a psycho-energizer. Was it a stimulator, did it enhance memory or learning abilities, or did it activiate the desire for acquiring more information ? As with our new psychotropic drugs, I don't know if it brought happiness and comfort, or new problems, aggravations, and urihappiness. Another example of early use and knowledge of medicinal plants we find in the fact that the most ancient medical god of Mesopotamia—Sin—was also the god of medicinal herbs. The development of drug chemistry brought: first, isolation from plants of a number of pharmacologically active substances (e.g. curare, atropine ouabain, etc.), later, synthesis of these entities and their derivatives; and finally, creation of completely new molecules, formerly not known, in the plant or animal kingdom. We know, also, that in the process of development and worship of chemistry we somehow forgot about our prime source, the plants. We forgot that we have used only some of the known substances of plant origin. At the same time, the intrusions of civilization have been progressively destroying the sources of our knowledge, as well as the source itself of many plants—plants which are used either in medicine or in ceremonial and sacred context. Today, time is running out if we want to save this information, and perhaps use for medicinal purposes some of the unknown compounds contained in plants. The idea of acquiring knowledge about these plants and compounds we have neglected or forgotten was the reason for organizing this symposium. It was self-evident that this meeting had to be multidisciplinary. We invited pharmacologists, pharmacists, chemists, biochemists, psychiatrists, anthropologists, etc., etc. We wanted to exchange existing information, confront dif ferent points of view, and outline and stimulate research objectives for the future. As one of the organizers of this symposium, I am certainly biased, but I feel that this meeting was very successful. I would like to include here the opinion of one of the participants. "This," he remarked, "is the first meeting I have attended that at the end of the sessions we had as many or even more participants than in the begining—this is a measure of the interest the meeting has created." We discovered after the meetings how many scattered researchers in wide and varied fields could contribute to the knowledge which we seek. This finding alone was one of the very important immediate gains from the symposium. And we hope that in the future we will be able to organize a second meeting on the same topics, and cover a much broader spectrum of problems in the ethnopharmacologic search for psychoactive drugs. The meeting was divided into six sessions, all but the first ending in panel discussions. D.E. Efron