Eleven patients are reported with unexplained gastrointestinal haemorrhage (GIH) presenting over a 2 year period in whom selective visceral angiography (SV A) was carried out after a negative endoscopy. SV A revealed the anatomical source of bleeding in all eleven patients and the aetiology in six of them. The latter comprised two tumours of the small bowel, an A-V malformation of the jejunum, enlarged pancreaticoduodenal vessels, angiodysplasia of the caecum and carcinoma of the rectum. Of the remaining five patients, four were seen to have active bleeding into the large bowel and one into the duodenum. Local surgical resection was carried out in nine patients, only one of whom rebled. There was one preoperative and one postoperative death. Experience with this technique has altered our management such that SV A is carried out sooner, saving the patient repeated admissions, investigations and transfusions. SV A is recommended as a pre-operative investigation for the surgeon managing acute unexplained GIH.