"Ayahuasca is a hallucinogenic tea originally from the Amazon Basin that is supposedly able to induce strikingly similar visions in people independent of their cultural background. Ayahuasca users commonly claim that this regularity across people’s visions is evidence that their visions are not simply the products of their own brains, but rather are representations of spiritual information learned from plant-spirits that one gains access to by drinking the tea."

Source

Anderson, Brian, "Entheogenic Visions: The Sacred Union of Word & Image," Undergraduate Humanities Forum, Mellon Research Fellows 2005-2006, Word & Image (Philadelphia, PA: May 5, 2006), pp. 2 and 30.