The most active alkaloid in ayahuasca is DMT, the tryptamine whose study initiated the current wave of psychedelic research and also occasioned some of the more intriguing juxtapositions of religion and science in the recent literature. In the early 1990s, the American psychiatrist Rick Strassman began doling out hundreds of injections of the powerful, short-acting tryptamine to seasoned volunteers at the University of New Mexico. Strassman’s study was designed to collect psychophysiological data, but his project was inextricably woven into broader religious and spiritual concerns on a number of fronts. Many of the volunteers experienced astounding and often terrifying encounters with alien or divine beings. These quasi-shamanic episodes disturbed Strassman and many of his subjects, and Strassman worried that the scientific mindset and clinical setting of the study (as opposed to more traditional or spiritual contexts) might be a leading factor in lending them a negative edge. These arguably 'religious' concerns contributed to his decision to discontinue the study in 1995.