The Amazonian sacramental decoction, ayahuasca, has been used traditionally for several millennia, apparently, for the explicit purposes of accessing altered states conducive to clairvoyance, precognition, telepathy, out-of-body travel, psychic diagnosis, psychic healing, and spirit communication. The psychoactive molecules known to be present within the brew, N,N-dimethyltryptamine (DMT) and the harmala alkaloids, are also present in the pineal gland of the human brain and are speculated to play an active role in dreaming. Furthermore, it has been speculated that these endogenous neurochemicals also play a primary neurological role in the occurrence of spontaneous psi phenomena. However, although the anthropological and anecdotal evidence for this hypothesis is good, the experimental evidence to date is scant, poorly controlled, and inconclusive. This paper reports on the preliminary findings of field research testing precognition ability with people under the influence of ayahuasca in Brazil and Ecuador and discusses the implications for transpersonal psychology.