Abstract:Two new triterpene saponins C and D have been isolated from the aerial parts of Polygala japonica Houtt. Their molecular formulas: C42H68O15 were structural isomers of each other. Acid hydrolysis of the two saponins all produced a sapogenin (2a, 3a, 24-trihydroxyo-lean-12-ene-28-oic acid) and D-glucoses. But only the saponin D could be hydrolyzed in the alkaline solution, the products were identical with those from acid hydrolysis. Their structures have been established by means of 1HNMR,13CNMR and MS as 3-O-[β-D-glucopyranosyl(l→2)β-D-glucopyranosyl] 2α, 3α, 24-trihydroxyolean-12-ene-28-oic acid, 28-O-[β-D-glucopy-ranosyl (1→2)-β-D-glucopyranosyl] 2α, 3α, 24-trihydroxyolean-12-ene-28-oic acid.