We previously reported that administration of bovine splenic alcohol extract (BSAE) mainly consisting of phospholipids augmented peritoneal macrophage function from normal mice but not spleen T cell function. In this study the effects of BSAE on peritoneal macrophages and spleen cells prepared from cancer-bearing mice were further examined to learn the efficacy of BSAE as an immunopotentiator. Following subcutaneous pre-administration of BSAE into C3H/He mice once a day for 14 days, the MM2 tumor cell line was implanted subcutaneously and BSAE administration was successively followed in the same way. BSAE administration enhanced phagocytosis, chemotaxis and TNF- α, IL-12 production by macrophages from cancer-bearing mice. BSAE effects on spleen T cells from cancer-bearing mice were also examined with the same schedule, although Meth-A cells were implanted into BALB/c mice similar to the procedures of MM2 implantation, including the use of BSAE. Although BSAE promoted the production of IL-2 and IFN-γ, it suppressed IL-4 production by spleen T cells from cancer-bearing mice. These results strongly indicate that BSAE administration leads to the activation of peritoneal macrophages as well as spleen T cells in cancer-bearing mice, suggesting the augmentation of cellular immunity.