Ayausca is a mixture of plants from the Amazon, capable of inducing altered states of consciousness, which normally last between 4 and 8 hours after ingestion.
With mild and stimulating, even visionary, effects, ayahuasca is used primarily as a cure and shamanic medium of communication, typically in ceremonial sessions with guides. The main ingredient of this jungle tea is a vineyard, Banisteriopsis caapi, which, just like the tea itself, is called ayahuasca (meaning "vine of the soul" or "vineyard with a soul").
The secondary ingredient can be the chacruna (Psychotria viridis) or the chagropanga (Diplopterys cabrerana), plants that contain a relatively high amount of the psychedelic substance DMT. Nobody knows with certainty since when this drink has been used.
The first record of Western contact with ayahuasca dates from 1851, by Richard Spruce, the famous English ethnobotanist. If we consider the archaeological evidences of the comparative use of native plants, it seems very probable that their use dates from hair less two millennia ago.
There is currently a lot of interest in the use of these sacred plants and articles about them can be read regularly in newspapers and magazines.