Randomized controlled trials (RCTs) have found positive results for psilocybin in obsessive-compulsive disorder and for both psilocybin and LSD in anxiety and depression in end-stage cancer. Our group in the Faculdade de Medicina, Universidade de Sa˜o Paulo, in Ribeira˜o Preto, in collaboration with the Universidade Federal do Rio Grande do Norte, was the first to report that a single dose of ayahuasca produced significant reductions in depressive and anxiety symptoms in 29 patients with treatment-resistant major depression disorder. For seven days after administration of the drug, greater symptom reduction was observed in the ayahuasca group than the control group. The preliminary but significant evidence of improvement in mood and anxiety disorders reported in RCTs, as well as the improvement in psychosocial adjustment, coping strategies and perceived social support reported in observational studies make us optimistic about the potential beneficial effects of these drugs, when used in carefully controlled contexts, whether clinical or ritual. Therefore, further clinical and naturalistic studies in larger samples are necessary to replicate these results and evaluate the long-term efficacy and safety of these compounds. Although these compounds are not ‘‘magic bullets’’ or ‘‘miracle drugs,’’ they indicate the possibility of a brave new world in psychiatric treatment, and we are cautiously optimistic about their potential.