Background: The therapeutic effects of the Amazonian plant tea ayahuasca may relate to its ability to enhance mindfulness capacities. Ayahuasca induces a modified state of awareness through the combined action of its active principles: the psychedelic N,N-dimethyltryptamine (DMT) and a series of centrally acting β-carbolines, mainly harmine and tetrahydroharmine. To better understand the therapeutic potential of ayahuasca, here we compared the impact on mindfulness capacities induced by two independent interventions: (a) participation in four ayahuasca sessions without any specific purpose related to improving mindfulness capacities; and (b) participation in a standard mindfulness training course: 8 weeks mindfulness-based stress reduction ...