Objective To investigate the relationship between acupuncture analgesia and cellular immunity, the acupuncture effect on expression of c fos mRNA, ppENKmRNA,iNOSmRNA and iNOS activity in the mouse peritoneal macrophage were studied. Methods Twenty BALB/c mice were randomly divided into 2 groups:a,the acupuncture group treated with 5Hz electroacupuncture (EA); b, the control group treated with no EA. The pain threshold was detected by K + ionophoresis method before and after EA or restraining. The experiment was performed by using in situ hybridization, NADPH NBT histochemistry, RNA dot blot and protein dot blot techniques. All dot blot signals were scanned for statistical analysis. Results The hybridization signals and iNOS activity appeared as granules in bluish violet color, localized in the cytoplasm of the macrophage. All dot blot signals were increased in the acupuncture group, when compared with those in the control group( P