Antiinflammatory action of phytolaccosides B and E isolated from the roots of Phytolacca americana was investigated and compared with that of aescin. Phytolaccoside B, when it was administered intravenously, exerted a potent inhibitory effect on the transudation caused by absorptive sponge pellet implanted s.c. in rats and on carrageenin induced edema in rats. Phytolaccoside E showed a weaker action than Phytolaccoside B did. Hemolytic potency of the saponins was decreased in the order of aescin, phytolaccosides B and E showing a same tendency as in antiinflammatory action. The experimental result suggests that the mode of action of phytolaccosides is the same as that of aescin.