To assess the efficacy and safety of the early administration of somatostatin in infusion during 72 hours plus 2 boluses, compared to placebo in the control of acute severe UGIB with suspicion of PUB.

Inclusion Criteria:

• Male or female non-cirrhotic patients at least 18 years old suspected to bleed from PU.
• Patients with haematemesis and/or hematochezia and/or melena which have been observed by a member of a clinical team (GP, hospital physician, nurse, ...).
• Either, documented signs of hypovolemia related to the current bleeding episode Or, occurrence of symptoms of hypovolemia

Exclusion Criteria:

• Treatment of the present bleeding episode with somatostatin or its analogues, vasoactive drugs, or endoscopic therapy.
• Any treatment with PPIs (IV or per os) within the last 48 hours preceding randomisation.
• Treatment (endotherapy or pharmacotherapy) for upper gastrointestinal ulcer bleeding in the last 30 days.
• Deficient haemostasis (platelets < 40 x 109/l, international normalised ratio of the prothrombin time > 1.5 (or prothrombin time < 70%), or activated partial thromboplastin time > 40 seconds (or according to the normal ranges validated, from local lab))
• Anticoagulant therapy (vitamin K antagonists or heparin including LMW heparins)
• Terminal stage illness in which endoscopy is contraindicated