Ilekudinol B is one of the flavonoids isolated from Weigela subsessilis (Caprifoliaceae). In the present study, the suppression effect of ilekudinol B on tumor necrosis factor $(TNF)-{alpha}-induced$ cyclooxygenase-2 (COX-2) expression was investigated in human colon epithelial cell line HT-29. Interleukin-8 (IL-8) production and prostaglandin $E_2;(PGE_2)$ secretion was measured by enzyme-linked immunosorbent assay (ELISA). COX-2 and nuclear factor $(NF)-{kappa}B$ expression were determined by Western blot analysis. Ilekudinol B significantly inhibited $TNF-{alpha}-induced$ secretion of IL-8 and prostaglandin $E_2;(PGE_2)$ from the human colon epithelial cell line HT-29 in a concentration-dependent manner. In addition, ilekudinol B remarkably diminished $TNF-{alpha}-induced$ COX-2 expression and $NF-{kappa}B$ p65 subunit translocation to the nucleus. In conclusion, our results indicate that ilekudinol B may have anti-inflammatory activity on $TNF-{alpha}-dependent$ colonic inflammation.