Abstract: Esculentoside A(EsA)is a kind of saponin isolated from Phytolacca esculenta Van Houtte. It was shown to significantly inhibit phagocytic activity ,intracellular and extracellular produc- tion of interleukin-1 by thioglycollate primed murine peritoneal macrophages in vitro at the concentra- tion 0.01～1.0μmol·L^-1.In vivo experiments showed that EsA 2.5～5mg·kg^-1 markedlydecreased serum hemolysin concentration in sensitized mice challenged with sheep red blood cells. Inhibition of antibody production by B lymphocytes,phagocytosis and the production of inflammatorymediators by macrophages may partially explain the wide and strong anti-inflammatory effect of EsA.