Acanthoic acid (AA) is a pimaradiene diterpene isolated from Acanthopanax koreanum. We examined the effect of AA in dextran sulfate sodium (DSS)-induced colitis. AA (100 mg/kg or 300 mg/kg) was administered p.o. daily for 7 days. AA significantly inhibited Disease Activity Index, histological score, and myeloperoxidase activity. Furthermore, AA markedly suppressed the protein expression of TNF-${alpha}$, COX-2, NF-${kappa}B$ and chymase as well as the mRNA expression of TNF-${alpha}$ and COX-2. These results suggest that AA exerts beneficial effects in experimental colitis, and therefore we propose that this compound may have therapeutic implications for ulcerative colitis.