The inhibitors of prostaglandin $E_2;(PGE_2)$ production and cyclooxygenase-2 (COX-2) activity have been considered as potential anti-inflammatory agents. In this study, we evaluated 9 compounds isolated from 5 Korean phytomedicinal plants (Spirea prunifolia, Paeonia suffruticosa, Salvia miltiorrhiza, Scutellaria baicalensis, and Artemisia capillaris) for the inhibition of $PGE_2$production and COX-2 expession in lipopolysaccharide (LPS)-stimulated human macrophages U937 cells. As a result, several compound such as prunioside A, penta-O-galloyl-beta-D-glucose, tanshinone IIA, baicalin, baicalein, wogonin, scopolatin, scoparone and decursinol showed potent inhibition of $PGE_2$production (50-70% inhibition at the test concentration of $10;{mu}M$). In addition, these compounds were also considered as potential inhibitors of COX-2 activity (45-73% inhibition at the test concentration of $10;{mu}M$). These active compound mediating COX-2 inhibitory activities are warranted for further elucidation of active principles for development of anti-inflammatory agents and these properties may contribute to the anti-atopic dermatitis activity.