The antiinflammatory activity of Phytolacca saponin and phytolaccagenin isolated from the roots of Phytolacca americana has been investigated. When Phytolacca saponin and phytolaccagenin were given parenterally exhibited potent inhibitory effects on acute edema in rats and in mice. while oral administrtion required 6 times more dosage in comparison with that of intrapertioneal injection. The anti-exudative and anti-granulomatous activities of the saponin showed as much as the dose of 8 times higher than that of hydrocortisone. The saponin appeared to be of no effects on adrenal, however, showed a severe thymolysis at high dose.