Endoscopic retrograde cholangiopancreatography (ERCP) is an endoscopic procedure used to diagnose and treat problems in the bile ducts and pancreas. One of its most common complications is **post-ERCP pancreatitis**. This multicenter randomized clinical trial will evaluate whether **cooling the duodenal papilla** with **sterile saline at 3°C** immediately after ERCP can reduce the risk of post-ERCP pancreatitis compared with standard ERCP care.

Adults **≥18 years** with a **native papilla** scheduled for diagnostic or therapeutic ERCP at **three high-complexity university hospitals in Bogotá/Cundinamarca (Colombia)** will be randomized **1:1** to: (1) **intervention**-instillation of **250 mL** of **3°C sterile saline** in **five 50-mL aliquots** directed to the papilla through the endoscope working channel at the end of ERCP, with aspiration between aliquots; or (2) **control**-standard ERCP with no additional instillation. The saline temperature will be verified immediately before administration. Standard preventive measures (e.g., rectal NSAIDs, lactated Ringer's hydration, prophylactic pancreatic stent when clinically indicated) may be used per usual care and will be recorded.

The **primary outcome** is post-ERCP pancreatitis at **24 hours**, defined using Cotton criteria (new/worsening abdominal pain plus serum amylase or lipase ≥3× the upper limit of normal). Secondary outcomes include pancreatitis severity, other ERCP-related complications, and safety through day 7 (including a telephone follow-up). Participants will be screened and consented before sedation; randomization occurs at the end of the ERCP; clinical assessment and labs are performed at 24 hours; follow-up continues through day 7.

Safety monitoring will include systematic assessment for potential effects related to local cooling (e.g., chills, duodenal spasm, mucosal bleeding at the instillation site, or clinically relevant hypothermia) at 2 and 24 hours, with surveillance for serious adverse events through day 7.

**Inclusion Criteria:**

• Adults **18 years of age or older**
• **Native (unmodified) duodenal papilla**
• Scheduled for **diagnostic or therapeutic ERCP**

**Exclusion Criteria:**

• **Inaccessible papilla** or papilla **surgically altered/modified**
• **Ongoing acute or chronic pancreatitis**
• **Pregnancy**
• **Ethical or medical contraindications to ERCP**
• **Lack of informed consent**