[en] ¹¹¹In-labelled leucocytes were used to obtain gamma camera images of inflamed of bowel in a wide variety of inflammatory bowel disease. No false positive scans were observed in the irritable bowel syndrome and in bowel malignancy. All patients with moderate or severely active disease had positive scans. Faecal excretion of ¹¹¹Indium increased with disease severity. ¹¹¹In-tropolone labelling appeared to offer the advantage over ¹¹¹In-acac labelling in localising inflamed bowel earlier. In many cases the bowel was imaged within 40 min of re-injection of the leucocytes. ¹¹¹In-leucocyte scanning provides a novel approach to the problem of diagnosis and assessment of inflammatory bowel disease. It is non-invasive, requires no bowel preparation and thus is safe in the acutely sick patient where conventional radiological imaging methods may be hazardous. ¹¹¹Indium faecal excretion provides an objective assessment of disease activity which should prove useful in evaluating treatment regimes