In this study, we investigated the anti-inflammation effect of Persicaria thunbergii (P. thunbergii) on RAW 264.7 murine macrophage cells. The anti-inflammatory activity of P. thunbergii was determined by measuring expression of the LPS-induced inflammatory proteins, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and nuclear factor-κB (NF-κB), and the production of nitric oxide (NO) and prostaglandin E2 (PGE2). Methanol extract of P. thunbergii decreased the expression of iNOS, COX-2 and NF-κB, and increased the expression of HO-1 in LPS-stimulated RAW264.7 cells. Methanol extract was fractioned by n-butanol, hexane and ethyl acetate (EtOAc) and each fraction was tested for inhibitory effects on inflammation. Among the sequential solvent fractions, the EtOAc soluble fraction was investigated by the expression of prostaglandin E2 (PGE2), and showed decreasing form to the dose-dependent manner. EtOAc extract showed the most effective inhibitory activity of the expression of iNOS, COX-2 and NF-κB, and the production of NO. The study showed that P. thunbergii has anti-inflammatory activity through the decrease of NO and inhibition of iNOS, COX-2, PGE2 and NF-κB expression, and by the increase of HO-1 enzyme. This study needs for more investigation to find out the most effective single compound with anti-inflammatory activity.