Prior to the Good Friday service, twenty graduate degree divinity student volunteers from the Boston area were randomly divided into two groups. In a double-blind experiment, half of the students received psilocybin, while a control group received a large dose of niacin. Niacin produces clear physiological changes and thus was used as an active placebo. In at least some cases, those who received the niacin initially believed they had received the psychoactive drug.[3]:5 However, the feeling of face flushing (turning red, feeling hot and tingly) produced by niacin subsided after about an hour after receiving the dose. However, the effects of the psilocybin intensified over the first few hours.

Almost all of the members of the experimental group reported experiencing profound religious experiences, providing empirical support for the notion that psychedelic drugs can facilitate religious experiences. One of the participants in the experiment was religious scholar Huston Smith, who would become an author of several textbooks on comparative religion. He later described his experience as "the most powerful cosmic homecoming I have ever experienced".[4]