The aim of this study was to clarify the anti-inflammatory mechanism of apigenin. Apigenin inhibited the collagenase activity involved in rheumatoid arthritis (RA) and suppressed lipopolysaccharide (LPS)-induced nitric oxide (NO) production in a dose dependent manner in RAW 264.7 macrophage cells. Pretreatment with apigenin also attenuated LPS-induced cyclooxygenase-2 (COX-2) expression. In addition, apigenin profoundly reduced the tumor necrosis factor-${alpha}$ (TNF-${alpha}$)-induced adhesion of monocytes to HUVEC monolayer. Apigenin significantly suppressed the TNF-${alpha}$-stimulated upregulation of vascular cellular adhesion molecule-1 (VCAM-1 )-, intracellular adhesion molecule-1 (ICAM-1)-, and E-selectin-mRNA to the basal levels. Taken together, these results suggest that apigenin has significant anti-inflammatory activity that involves blocking NO-mediated COX-2 expression and monocyte adherence. These results further suggest that apigenin may be useful for therapeutic management of inflammatory diseases.