The pharmacological properties of seven pure saponins isolated from Panax ginseng C. A. Meyer were studied. 1. The ginseng saponins showed weak toxicities in mice. Especially, Rg1, Rf and Rb 1, which contained glucose as a sugar component, were weaker in their toxicities than the rest, which contained arabinose and/or rhamnose. It was also noted that the saponins containing protopanaxadiol as sapogenin were more toxic than those containing protopanaxatriol. 2. All the saponins diminished ACh-induced contraction of the isolated ileum of the guinea pig. On the other hand high concentrations of Rb 2 caused contraction of the ileum by itself. 3. All of the saponins induced a decrease in heart rate and showed biphasic actions on the blood pressure in rats, while they little affected respiration. They caused blood pressure fall preceded by slight rise. Among them, Rg 1 showed the most prominent action and it produced a blood pressure rise with doses of 30 to 100 mg/kg. The pressor as well as depressor action was not influenced by the pretreatment with any of atropine, diphenhydramine, phentolamine and propranolol. 4. Rg 1 and Re showed vasodilator action in dogs, the potencies of which were 1/20 and 1/50 of that of papaverine, respectively. Rc and Rb 2 showed very weak vasodilator actions but Rb 1 did not. 5. Among the 7 saponins, Rd, Re and Rb 2 showed more potent hemolytic actions than those of the rest and the potencies were proportional to their toxicities. 6. Whereas single administration of Rf, Re and Rd significantly suppressed the conditioned avoidance response, repeated administration of them caused facilitation of the response. On the other hand, Rb 2 always showed very weak suppressant action. 7. Rg 1, Rf, Re and Rd significantly suppressed the fighting of mice induced by foot shock, while Rb 1, Rb 2 and Re little affected the fighting. 8. All the saponins showed antifatigue action. They markedly increased the movement after compulsory gait and the action was consistent and independent of their action on the movement before compulsory gait. 9. The saponins showed moderate depressant actions on the EEG and the behavior in cats. They were qualitatively similar in their actions, although Rg 1, Re and Rb 2 were more potent than the rest. They also suppressed EEG arousal response induced by electrical stimulation of the mid brain in cats.