The influences of the polysaccharide extracts of a medical fungus-Xylaria nigripes on the activity of mice macrophage was studied. It was found that the polysaccharide extracts was capable of activating macrophage to produce cytotoxicity and then to inhibit proliferation of tumor cells (EAC) in vivo,whereas it didn't in vitro.In addition the release of IL-1 and phagocytosis of M are increased with the polysaccharide extracts. The results suggested that Xylaria nigripes polysaccharide increase the immunity a...