A tale of two diseases: the history of inflammatory bowel disease.

'Inflammatory bowel disease' (IBD) sounds like a straightforward term - a disease of inflammation in the bowel. However, the history of IBD reveals a story of a nefariously complex set of idiopathic conditions. IBD defies definition, in part because its pathophysiology is not completely understood. For the same reason and despite substantial advances in research, IBD also defies cure. At best, IBD can be defined as a disease of disruption - disrupted physiology, microbiology, immunology and genetics. The term 'IBD' is most often used to describe two separate conditions: ulcerative colitis (UC) and Crohn's disease (CD). This paper reviews the history of IBD, considering the ever-evolving understanding of both UC and CD. Beyond its intrinsic interest, the history of IBD exemplifies a pattern that is becoming increasingly familiar in the 21st century - the story of a chronic, incurable disease that defies the best efforts to treat it.