Objectives : The aerial parts of Rumex japonicus Houtt. (RF) is used by traditional clinics to treat parasite infection in East asia. This study aims a verification of anti-oxidative and anti-inflammatory effects of RF methanol extract. Methods : Anti-oxidative effects of RF were measured by scavenging activities of DPPH, superoxide, nitric oxide (NO) and peroxynitrite radicals. And also scavenging activities of anti-oxidation in lipopolysaccharide (LPS)-treated RAW 264.7 cells were measured. The inhibitory effects against the production of inflammatory mediators including NO, prostaglandin $E_2$ ($PGE_2$), tumor necrosis factor-${alpha}$ (TNF-${alpha}$), interleukin-$1{eta}$ (IL-$1{eta}$), IL-6, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and the translocation of nuclear factor (NF)-${kappa}B$ in LPS-stimulated RAW 264.7 cells by RF were tested. Results : RF scavenged DPPH, superoxide, NO and peroxynitrite radicals, and RF (at $200{mu}g/m{ell}$) reduced the inflammatory mediators definitely. Conclusions : These results indicate that RF may be a potential drug source for oxidative stress related inflammatory diseases.