Patients with upper gastrointestinal bleeding will be randomized to two diagnostic groups ("early and late evaluation", or "late evaluation") in order to analyze the influence of early diagnostic evaluation on disease management, clinical course and patient satisfaction. The study design will also allow a comparison of the endoscopic findings when done early and late in the patient's course and an appraisal of the role of repeat diagnostic evaluation. The "early and late evaluation" group will undergo immediate endoscopy followed by an upper gastrointestinal series or angiography if necessary to find the source of bleeding. Patients in this group will then have an UGI series and repeat endoscopy done five days later. The "late evaluation" group will have no diagnostic procedures (with exceptions for those in immediate need of surgery) until the fifth day of the study. Patients in either diagnostic group with massive or persistent bleeding will be further randomized to initial treatment with surgery or intra-arterial vasopressin in order to contrast these two widely-used forms of treatment with respect to mortality, cessation of bleeding and complications. We will also estimate the value of the alternate treatment when given after the initial randomized treatment has failed to control bleeding.