In macrophages, nitric oxide (NO) is released as an inflammatory mediator and has been proposed to be an important modulator of many pathophysiological conditions including inflammation. In this study, we have examined the inhibition effects of NO production by 85% methanol extract of the flower of Pueraria thunbergiana (PF) in mouse macrophages. Extract of PF (1, 10, 100 ${mu}g/ml$) inhibited NO production, inducible NO synthase and cyclooxygenase-2 expression in interferon-g and lipopolysaccharide-stimulated mouse peritoneal macrophages and it had no cytotoxicity. These data suggest that 85% methanol extract of PF might be useful in controlling macrophages mediated inflammatory disease.