Peptic ulcer bleeding is the most common etiology in upper gastrointestinal bleeding all over the world. After endoscopic treatment, proton pump inhibitor (PPI) is recommended to prevent re-bleeding. Intravenous PPI is recommended as a standard treatment. In the past, there were many trials showing the efficacy of high-dose oral PPI after endoscopic hemostasis but most were industrial sponsor which assessing an expensive PPI. Moreover, the number of patients in those studies were insufficient to confirm a non-inferiority outcome in term of rebleeding by using oral PPI. This study will evaluate a high-dose, local-made PPI (omeprazole) in peptic ulcer treatment after successful endoscopic hemostasis compared to standard IV PPI continuous drip in term of rebleeding, as well as 24-hour gastric pH monitoring.

Inclusion Criteria:

• Patients with peptic ulcer bleeding and endoscopic finding show ulcer with Forrest classification Ia (spurting haemorrhage), IIa (oozing haemorrhage), Ib (non-bleeding visible vessel)
• Age > 18 years old

Exclusion Criteria:

• Deny to participate
• Pregnancy or lactation
• Low risk peptic ulcer bleeding including clean base ulcer, flat pigmented spot
• Non-peptic ulcer bleeding eg. erosive gastritis/duodenitis, Mallory Weiss tear, esophageal/gastric/duodenal varices, vascular lesions (eg. Dieulafoy) , malignant ulcer
• Bleeding tendency
• Terminal stage of cancer
• ESRD on hemodialysis
• Decompensated liver cirrhosis

The outcomes assessor will not know the assigned treatment.