Over a four-year period, eight patients with documented gastrointestinal bleeding had angiography as a part of their investigation and treatment at the Department of Radiology, Victoria General Hospital, Halifax, Nova Scotia. A review of these eighty cases has been carried out and angiography has been found to be both safe and reliable in the diagnosis of gastrointestinal bleeding. Cautiously administered intra-arterial pitressin infusion therapy will arrest bleeding in about one-third of cases and in most others will reduce blood loss so that a critically ill patient may be made more fit for subsequent surgery. Patients who have recently received intravenous pitressin should not be given intra-arterial pitressin.