This paper describes the experience with 99m Technetium labelled red blood cell (99mTc RBC) scintigraphy in twenty-two patients presenting with acute gastrointestinal (GI) tract bleeding. Studies were positive in thirteen cases--eight from the lower GI tract and five from the upper. The data from surgical intervention were available in ten cases. Scintigraphy cannot diagnose the cause of GI bleeding, as it is a nonspecific study. Its usefulness lies in its ability to accurately diagnose the bleeding site, as was shown in this study where there was good surgical correlation. The simplicity, reproducibility and reliability of the technique, particularly when bleeding rates are low and intermittent, make it, in our view, the first line of investigation in any patient with suspected bleeding from the colon or upper GI tract if endoscopic evaluation is not possible in the latter. Its current under-utilisation in the Caribbean may be a reflection of the lack of nuclear imaging facilities.