Ayahuasca is a botanical hallucinogenic preparation which is made up of Banisteriopsis caapi and Psychotria viridis, consumed by indigenous groups of the Amazonia region. This beverage contains the serotoninergic agonist N,N-dimethyltryptamine (DMT) and monoamine oxidase-inhibiting alkaloids (harmine, harmaline and tetrahydroharmine). Scientific literature has until now suggested that the administration or acute consumption of ayahuasca is not badly tolerated, even in situations where consumers have endured chronic use of the substance, no study having detected any effect of toxicological nature in humans. However, taking into account the limitations of performing most studies on a young and healthy sample, and the scant data on preexisting hepatic and cardiac pathologies, as well as the combined use of ayahuasca with other substances, a warning about the contraindication of ayahuasca use is suggested.