Aim In order to find out the effect of polysaccharide krestin(PSK) on nitric oxide (NO) production in mouse peritoneal macrophages. Methods The content of NO in cell cultures was analyzed by a method using Griess reagent, and the cell number was determined by staining with crystal violet. Results Without any stimulation,there was no alteration of NO production in mouse peritoneal macrophages by PSK primed, but when the cells were stimulated with lipopolysaccharide (LPS), NO production increased ...