Inflammatory bowel disease (IBD) is the term applied to a group of poorly understood intestinal conditions characterized by inflammation of the lining of the stomach and intestines. It is one of the most common findings in cats presented for the investigation of vomiting, diarrhea, weight loss and anorexia. Not surprisingly, treatment of IBD is non-specific. Recent advances in the understanding of the immune and inflammatory processes in people and animals have enabled the underlying intestinal inflammation to be defined more clearly. This has directly resulted in the development of drugs aimed at inflammation, some of which are now in clinical trials. The objective of the present study is to further understand the inflammatory and immune responses of the gastrointestinal tracts of cats with naturally occurring IBD. It is anticipated that the proposed study would substantially advance our understanding of IBD, facilitate distinction of IBD from cancer, and help to define specific targets for therapy in the future.