The methanol extract of Zanthoxylum rhetsa (MZRR) were evaluated for its ability to suppress the formation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages. MZRR presented an inhibition of LPS-induced production of nitric oxide (NO) and prostaglandin $E_2$ ($PGE_2$) in RAW 264.7 macrophages. Western blotting and RT-PCR analyses demonstrated that MZRR significantly inhibited the protein and mRNA expressions of iNOS and COX-2 in LPS-activated macrophages in a dose-dependent manner. LPS-induced COX-2, iNOS, and nuclear factor kappa beta (NF-${kappa}B$) activity were also decreased in the presence of MZRR. The production of tumor necrosis factor-$alpha$ (TNF-$alpha$), the mRNA expression levels of pro-inflammatory cytokines, including TNF-$alpha$ and IL-$1{eta}$, were reduced after MZRR administration in a dose dependent-manner. These results suggest that the MZRR extract involved in the inhibition of iNOS and COX-2 via the NF-${kappa}B$ pathway, revealing a partial molecular basis for anti-inflammatory properties of the MZRR extract.