Ayahuasca is a traditional psychoactive sacrament that's been used in Amazonian shamanic rituals for hundreds of years. Ayahuasca is notorious for its psychedelic properties produced from the combination of monoamine oxidase inhibitors (MAOIs) found in the Banisteriopsis caapi vine and N-N-dimethyltryptamine from Psychotria viridis or Diplopterys cabrerana. Recently, ritual use of ayahuasca has increased and garnered attention for its potential in treating mental illnesses, such as substance use and depressive disorders. Due to its MAOI properties, there are serious drug interactions that may be of concern among patients who participate in ayahuasca use. The objectives of this paper are to describe ayahuasca's pharmacology, potential drug interactions, and clinical data for its treatment potential in psychiatric illness. Keywords: ayahuasca, monoamine oxidase, dimethyltryptamine, sacrament, harmine