Acute pancreatitis (AP) is an inflammatory condition of the pancreas following the activated pancreatic enzymes induced by varied causes, with or without other organ(s) dysfunction. The production and release of inflammatory factors is generally considered as the key factor of pathogenesis. Non-steroidal anti-inflammatory drugs (NSAIDs) are the most commonly applied agents for inflammatory diseases. A series studies have proved that indomethacin can reduce the risk of post-endoscopic retrograde cholangiopancreatography (ERCP), but high-quality evidence is still lacking in the field of effectiveness of NSAIDs to treat, rather than prevent, other types of AP. Majority of animal experiments showed that NSAIDs had protective effects for organ functions, but the results of several preliminary clinical studies were inconsistent. Randomized controlled trials are eagerly awaited to elucidate its effects on AP.

Inclusion Criteria:

• All patients ages 18-80 years with a diagnosis of AP based on at least 2 of the following criteria:
• Abdominal pain characteristic of AP
• Serum amylase and/or lipase ≥ 3 times the upper limit of normal
• Characteristic findings of AP on abdominal CT scan will be screened for study enrollment.

Exclusion Criteria:

• Onset time >24 hours
• Presence of renal dysfunction (serum creatinine > 1.5 *normal upper limit)
• Severe liver dysfunction
• Active peptic ulcer disease or GI bleeding
• Pregnancy or breast-feeding
• Hypersensitivity to NSAIDs
• New-onset, exacerbation or uncontrolled hypertension
• Presence of serious cardiovascular events, including severe heart failure, myocardial infarction (MI) and stroke
• Mental disability
• Malignancy-associated acute pancreatitis
• Post-ERCP pancreatitis
• Informed consent not signed