The results of indium-111 tropolonate leucocyte scintigraphy in 105 patients with known inflammatory bowel disease are reviewed. Scintigraphy is as sensitive as radiology in detecting and assessing the extent of active colonic disease, and probably more sensitive in assessing small bowel disease. In a further 40 patients scintigraphy was successfully used as a screening test to identify, or exclude, bowel inflammation in patients with gastrointestinal symptoms. Scintigraphy has advantages over barium studies, being safe, non-invasive, more sensitive than small bowel radiology and giving additional information such as the bowel identification of intra-abdominal abscesses. The time required to label the leucocytes (about 2 hours) and the higher unit cost, unless many scintigrams are performed, are disadvantages.