This experiment was performed to investigate the effects of ginseng saponin fractions (total saponin, triol saponin. diol saponin) and lipopolysacrharide (LPS) on the tllmoricidal activity of macrophage. The ginseng saponin fractions had little effect on the tumoricidal activity of macrophage (less than 10%). When the ginseng saponin fractions were treated with LPS, the effects of tumoricidal activation of macrophage increased a relatively high percent, and the total saponin and triol saponin (20-35%) were ulore effectual than diol saponin (15-25%). The effects of ginseng saponin and LPS on the tumoricidal activity of macrophage were mediated by the induction of macrophage-release factor(5) which has(have) the capacity of tumor cell killing. And the quantity of the (actors) was(were) increased by the contact of macrophage with tumor cell.