Banisteriopsis caapi, also known as ayahuasca, caapi or yagé, is a South American liana of the family Malpighiaceae. It is used to prepare ayahuasca, a decoction with a long history of entheogenic uses as a medicine and "plant teacher" among the indigenous peoples of the Amazon Rainforest. It contains harmine, harmaline, and tetrahydroharmine, all of which are both beta-carboline harmala alkaloids and MAOIs. The MAOIs in B. caapi allow the primary psychoactive compound, DMT (which is introduced from the other primary ingredient in ayahausca, the Psychotria viridis plant), to be orally active. The stems contain 0.11-0.83% beta-carbolines, with harmine and tetrahydroharmine as the major components. Alkaloids are present in all parts of the plant.