Ayahuasca is a hallucinogenic brew that has N,N-Dimethyltryptamine and β-carbolines as its main component, and is a product of the decoction of Banisteriopsis caapi and Psychotria viridis. Although it produces acute somatic, cognitive and subjective manifestations, there are almost no reports of very adverse effects after ayahuasca-induced intoxication. This article presents the case of a 40-year-old male, from the Peruvian Amazon, who developed psychosis after a ritual intake session, later favorably resolved with specific treatment. Even though infrequent, these episodes may be quite severe and associate with violent behaviors. Ayahuasca users with a previous history of psychosis, mania, or substance abuse seem to be at higher risk. There are very few conclusive studies related to ayahuasca asa potential causal agent of psychosis, reason for which it is important to carefully evaluate and report cases similar to the one here described.