The relative potency of amphetamine derivatives and N,N-dimethyltryptamine (DMT) derivatives was evaluated in rats trained to swim through an underwater tube in order to escape at the other and of the tank. All of the compounds tested significantly increased the starting latency. The time of peak effect of 2,5-dimethoxy-4-ethyl-amphetamine (DOET), 2,5-dimethoxy-4-methyl-amphetamine (DOM), and 6-hydroxy-DMT was estimated at 40 min after the intraperitoneal injection and that of DMT, 4-methoxy-DMT, and psilocybin was 20 min. Dose-response curves showed that the increase in the latency was dose-dependent. The descending rank order of potency of the compounds, according to the median effective dose (ED50), was: DOET, psilocybin, DOM, DMT, 4-methoxy-DMT, and 6-hydroxy-DMT.