Book excerpt: Inflammatory bowel disease (IBD) encompasses a spectrum of autoimmmune diseases which include ulcerative colitis, Crohn’s disease, and indeterminate colitis. Ulcerative colitis is a relapsing nontransmural inflammatory disease restricted to colon, which may be classified as proctitis, left-sided colitis, or pancolitis depending on the extent of involvement. Some patients also develop ileal inflammation (backwash ileitis), which occasionally complicates its differentiation from Crohn’s ileocolitis. Crohn’s disease is defined as a relapsing transmural inflammatory disease of gastrointestinal mucosa that may affect the entire gastrointestinal tract (GIT) from the mouth to the anus. There is discontinuous involvement of various portions of the GIT and may get complicated by formation of strictures, abscesses, or fistulas. It closely resembles intestinal tuberculosis both clinically and on investigations. GI tuberculosis is often suspected on the basis of its clinical, radiological, and endoscopic features, but histological or microbiologic proof of the disease is often difficult to achieve. Therefore, the majority of patients are treated with antitubercular drugs on presumptive diagnosis only. Similar clinical, endoscopic, radiological, and histological features of GI tuberculosis and Crohn’s disease pose a serious challenge to the treating physician. The rate of misdiagnosis of these conditions using conventional diagnostic measures has been reported to be around 50–70%. Thus differentiation and diagnosis of these conditions is difficult but very important for correct treatment of the patients. Recently some serological tests have come up for diagnosing Crohn’s disease and ulcerative colitis, which may help to distinguish these disorders from each other and from GI tuberculosis. Besides diagnosis, treatment for IBD is also an emerging field in which active research is going on. The traditional drugs used in treatment of IBD include steroids and aminosalicylates. Recent studies have evaluated the role of azathioprine, methotrexate, and cyclosporine. Apart from improving efficacy of therapy in short term, these agents have raised debate on complications of therapy, long-term efficacy, and cost. Management of IBD during pregnancy and fistulising Crohn’s disease are other areas of concern.