The Ayahuasca tea has been used for more than a thousand years by the Indians of South America, as a spiritual and ritualistic instrument, for religious purposes. Non-Indians sects have arose in the last century, and started to use the tea. This utilization is increasing since the legalization of the Ayahuasca for religious use in Brazil. The effect of the tea is caused by the presence of alkaloids in the plants used in its preparation: the Banisteriopsis caapi liana, and the leaves of Psycotria viridis shrub. The effects observed are: hallucination, hypertension, tachycardia, nausea, vomiting and diarrhea. These actions may cause more serious damage to the organism, and therefore deserve more attention from the health professionals, because even for strickly religious use the tea may cause higher biological damage and therefore, the users should be made aware of the possible toxic effects of these substances.