To study the effects of ginseng saponin components on the signal transduction in the ac tivation of murine macrophages, phagocytosis and Intracellular calcium concentration of peritoneal exuded mouse macrophages were examined. The phagocytosis was increased significantly after treatment with total saponin, diol-saponin, $Rg_1$ and $Rg_2$, but triol-saponin was unable to increase phagocytosis. The phagocytosis were increased when H7, a PKC inhibitor, was pretreated and increased significantly by saponin fractions except total saponin. Pertussis toxin, which inactivates G-protein, decreased the phagocytosis. But the phagocytosis was restored to the control level by saponin fractions and the phagocytosis was increased significantly by $Rg_2$ and $Rg_2$. The triol saponin increased phagocytosis approximately by 2-fold as compared with the TMB-8 treated group. Peritoneal exuded macrophages displayed a prominent rise in cytosolic calcium following treatment with triol-saponin, $Rg_1$, $Rg_2$ and $Rg_2$. Incubation of macrophages with PT resulted in an inhibition of cytosolic calcium mobilization, but increased cytosolic calcium mobilization with saponin fraction.