inflammatory bowel disease ibd is a broad term that describes conditions with chronic or recurring immune response and inflammation of the gastrointestinal tract the two most common inflammatory bowel diseases are ulcerative colitis and crohn s diseasenflammatory bowel disease ibd is a broad term that describes conditions with chronic or recurring immune response and inflammation of the gastrointestinal tract the two most common inflammatory bowel diseases are ulcerative colitis and crohn s disease