Cucurbitacins are a natural cell-permeable triterpenoid compound isolated from Cucurbitaceae and Cruciferae. Cucurbitacins have been used as folk medicine because of their anti-inflammatory and analgesic effects. In the present study, we investigate the anti-cancer effects of cucurbitacin I on colitis-associated colon carcinogenesis induced by azoxymethane (AOM)/dextran sodium sulfate (DSS) in BALB/c mice. Cucurbitacin I treatment attenuated loss of body weight and decreased the number of colon tumors. Western blot analysis showed that cucurbitacin I treatment significantly inhibited the protein expression of inducible nitric oxide synthase (iNOS), tumor necrosis factor (TNF)-${alpha}$ and interleukin (IL)-6. These results suggest that cucurbitacin I suppressed inflammatory reaction and tumor development in colitis-associated colon carcinogenesis.