Abstract: The sedative action of Rauwolfia A, a water-soluble alkaloid isolated from Rauwolfia verticillata (Lour.) Baill., was investigated in mice in comparison with reserpine by the following methods: potentiation of hexobarbital narcosis, squirrel wheel, rolling cylinder and jiggle cage. Quantitatively, reserpine was found to be 17—35 times more active than Rauwolfia A. The marked difference in gross behavior of mice was also observed after the administration of these two drugs. In the rabbit's conditioned food motor reflex experiments, intravenous injection of Rauwolfia A 1 mg/kg prolonged the latency of conditioned reactions, partly abolished the conditioned reflexes and partly disturbed the differentiation. The same effect on positive conditioned reflexes was obtained with reserpine 0.1 mg/kg, and the action was much more persistent but the differentiation remained normal. Intraperitoneal injection of 5 mg/kg Rauwolfia A yielded essentially the same results in cat's conditioned food motor reflexes as in rabbits. From the above-mentioned data, it may be concluded that Rauwolfia A does not possess the characteristic sedative effect of reserpine.