G. japonicum is a perennial hem and the flowering plant has been used as a diuretic and an astringent in Japan and China. However, little information is available about the anti-inflammatory action of G. japonicum. Therefore, the objective of this study was to investigate the antiinflammatory action of fractions from G. japonicum methanol extract. Inhibition of NO production was observed when cells were cotreated with fractions of G. japonicum and lipopolysaccharide. We observed that ethyl acetate fraction of G. japonicum inhibited NO production by LPS-activated RAW 264.7 cells, and that the suppression induced by ethyl acetate fraction of G. japonicum was associated with antioxidant activity and direct NO clearance. In addition, only ethyl acetate fraction of G. japonicum inhibited stimulated $PGE_2,;TNF-alpha,;IL-1eta$ production, whereas water and methyl chloride fractions showed no such effects. The ethyl acetate fraction of G. japonicum methanol extract showed a remarkable scavenging activity on the 1,1-diphenyl-2 picrylhydrazyl radical. Based on the results, ethyl acetate fraction of G. japonicum may be useful source as natural antioxidants and antiinflammation. Therefore, the results obtained from this study provide an alternative protective mechanism of ethyl acetate fraction of G. japonicum and provide information on the potential use of ethyl acetate fraction of G. japonicum in chemoprevention or pathogenic conditions related to overproduction of NO and $PGE_2$. However, the mechanism of the inflammatory effect must be evaluated through various parameters for induction of NO production.