Dimethyltryptamine is a hallucinogenic indole. It also occurs naturally in many species of plants. DMT-containing plants are used in several South American shamanic practices. It is one of the main active constituents of snuffs like yopo and of the potion ayahuasca. DMT is a powerful psychoactive substance. If DMT is smoked, injected, or orally ingested with an MAOI, it can produce powerful entheogenic experiences including true hallucinations (perceived extensions of reality). A trip sitter is often employed to assist the drug user stay physically and mentally healthy, and, in the case of smoked DMT, to catch the pipe when the user loses awareness of it. Induced DMT experiences can include profound time-dilation, time travel, journeys to paranormal realms, and encounters with spiritual beings or other mystical/trans-dimensional modalities that, by most first hand accounts, defy verbal or visual description.

DMT, which is broken down by the digestive enzyme monoamine oxidase, is inactive if taken orally, unless combined with a monoamine oxidase inhibitor (MAOI). Harmala is ofen used as an MAOI to facilitate the oral ingestion of DMT and other tryptamines; it is also hallucinogenic on its own.

DMT is classified in the United States as a Schedule I drug and in the United Kingdom as a Schedule I/Class A drug. In Brazil there are a number of religious movements based on the use of Ayahuasca, as part of shamanistic rituals and these were legalized recently.

Formal Chemical Name (IUPAC)
2-(1H-indol-3-yl)-N,N-dimethylethanamine

References

http://en.wikipedia.org/wiki/Dimethyltryptamine

http://en.wikipedia.org/wiki/Ayahuasca