In four patients, women aged 65 and 86 years and men aged 22 and 46 years, admitted with profuse loss of fresh blood per anum, acute haemorrhage in the lower gastrointestinal tract was diagnosed. A ...systematic diagnostic and therapeutic strategy increases the possibility of localising the bleeding site in such patients. Urgent colonoscopy after oral purge for cleansing the colon of stool is feasible, safe and often both diagnostic and therapeutic. Dependent on local expertise, erythrocyte scintigraphy and (or) mesenteric angiography can further improve the locating of the bleeding site. However, in 10% of the patients the bleeding site remains unclear. In these cases surgical intervention may be necessary. Additional peroperative endoscopy, injection of methylene blue via a selective catheter or the construction of multiple stomas can be helpful. Blind colon resections should be avoided. The localisations in the four patients were: angiodysplastic focus in the caecum, a superficially eroded vein in the ileum, a Meckel's diverticulum, and multifocal vasculitis.
