The Western diet characterized by high fat and high sugar is considered a risk factor for inflammatory bowel disease (IBD) such as colitis. However, the precise role of sugar in colitis pathogenesis is poorly understood. We, therefore, investigated the role of glucose, a simple sugar, in colitis pathogenesis using IBD susceptible Il10-/- mice. We fed healthy 14-week old Il10-/- mice with 10% glucose in drinking water for 5 week and monitored body weight changes. Sugar fed Il10-/- mice spontaneously developed severe colitis, characterized by higher body weight loss and increased diarrhea, and shorter colon lengths.