Eight phenolic compounds (1-8) which were isolated from the barks of Ulmus macrocarpa were evaluated for their inhibitory activities on nitric oxide (NO) and prostagrandin $E_2$ (COX-2) production in $interferon-{gamma};(INF-{gamma})$ and lipopolysaccharide (LPS)-activated RAW 264.7 cells in vitro. NO and COX-2 levels were moderately reduced by the addition of compounds (1-8). Among them 3,4,5,6,7 and 8 inhibited NO production in a dose dependent manner with an $IC_{50}$ of 92.2, 97.3, 36.1, 43.5, 32.8, 39.4 and 37.1 ${mu}g/ml$, respectively (positive control, L-NMMA; 36.4 ${mu}g/ml$), and 3,4,5,6,7 and 8 reduced the COX-2 level in a dose dependent manner with an $IC_{50}$ of 43.2, 24.8, 24.8, 33.4, 44.8 and 22.7 ${mu}g/ml$, respectively (positive control, indomethacin; 23.4 ${mu}g/ml$). These results suggest that the phenolic compounds may be developed as potential anti-inflammatory and cancer chemopreventive agents.