Ayahuasca, also known as iowaska, or yagé, is an entheogenic brew made out of Banisteriopsis caapi vine and other ingredients. The brew is used as a traditional spiritual medicine in ceremonies among the indigenous peoples of the Amazon basin and is known by a number of different names.
B. caapi contains several alkaloids that act as monoamine oxidase inhibitors (MAOIs). Another common ingredient in ayahuasca is the shrub Psychotria viridis, which contains the primary psychoactive, dimethyltryptamine (DMT). MAOIs are required for DMT to be orally active.