Ayahuasca (Banisteriopsis caapi and Psychotria viridis
Ayahuasca is a tea prepared from the Banisteriopsis caapi vine and the leaves of Psychotria viridis. Psychotria viridis leaves contain Dimethyltryptamine (DMT). DMT depending on the  consumed dose results can range from short-lived milder psychedelic states to powerful immersive experiences. Banisteriopsis caapi contains three main compounds that have physical effects: harmine, harmaline and tetrahydroharmine. Harmine and harmaline are Monoamine oxidase inhibitors (MAOI) they specifically inhibit MAO-A (CALLAWAY J.C. et al, 1999). The presence of these compounds in the tea prevents the metabolism of DMT in the stomach and intestines allowing it to reach the blood stream and the brain. Tetrahydroharmine is a serotonin uptake inhibitor (CALLAWAY J.C. et al, 1999).

Ayahuasca largely used for religious purposes but also has traditional medicinal applications. The ritual is a spiritual it is intended as a purification. Ayahuasca translates to “spirit vine” in Quechua. The harsh diarrhea and vomiting associated with is used to purge the body of parasitic worms. Harmala alkaloids themselves have been shown to be anthelmintic (ANDRITZKY, 1989).

It has been used in Amazonia for centuries. Christian missionaries encountered its use in the 16th century. They equated its use with Satan. The active compounds of Banisteriopsis caapi were isolated in the 20th Century. A number of modern religious movenments in Brazil extensively use Ayahuasca. Santo Daime, established in the 1930s integrates ayahuasca with Christianity. Since the 1990’s the movement has followers around the world.

Legally DMT is still listed as a schedule one substance. Due to their usage of ayahuasca as a sacrament and the spread of the religion, Santo Daime has found itself the center of Court battles and legal wrangling in various countries. In March 2009, there was court ruling that the utilization of ayahuasca for religious ceremonies was legal in the United States (ANDRITZKY, 1989).

Callaway, J.C., et al. (1999). "Pharmacokinetics of Hoasca alkaloids in healthy humans". Journal of Ethnopharmacology 65 (3): 243–256.
Andritzky, W. (1989). "Sociopsychotherapeutic functions of ayahuasca healing in Amazonia". J Psychoactive Drugs 21 (1): 77–89.