The consideration of haematemesis and meleena, mainly associated with peptic ulcer, must inevitably recur from time to time, since there is still a high mortality in haemorrhage from the upper gastro- intestinal tract and no universal routine in management has been established. This enquiry, then, is an attempt to establish criteria, firstly for diagnosis, secondly for prognosis and, in the light of these, to determine subsequent procedure in treatment. The subject matter is based on the findings in 120 cases of bleeding from the upper gastro -intestinal tract which came under the care or personal observation of the writer between 1942 and 1947. It is concerned mainly with the diagnosis and treatment of haemorrhage, particularly of the massive type, arising from peptic ulcer; ulceration was present in 110 cases of this series. The patients were seen in general practice, in the Preston Royal Infirmary, where the writer had a radiological appointment, and in St. Joseph's Hospital, Preston, where he was visiting physician. Post mortars findings were used as the enquiry progressed in order to assess diagnosis and to correct errors.