Endoscopic retrograde cholangiopancreatography (ERCP (, a key tool that is used in diagnosis and treatment of pancreato-biliary diseases. Post-ERCP pancreatitis (PEP) is the most common and serious complication that can occur following this procedure and can lead to significant morbidity and mortality. A variety of patient-related and procedure-related factors have been associated with higher rates of PEP.

Inclusion Criteria:

1. Age more than 18 years old.
2. Gender: Males and Females
3. Patients with suitable indications for ERCP due to suspected pancreato-biliary disorders.
4. Blood amylase and lipase levels before ERCP are within the normal limits.

Exclusion Criteria:

1. Age of less than18 years.
2. Uncontrolled diabetes mellitus (DM)
3. Severe bleeding tendency
4. Impaired renal function (serum creatinine > 2 mg/dL), (creatinine clearance <30 ml/min)
5. Patients with severe heart disease.
6. Subjects who underwent prior biliary or pancreatic sphincterotomy or dilatation or stenting of either duct.
7. Currently pregnant or nursing
8. Admission due to established pancreatitis before ECRP
9. Unwillingness to undergo ERCP.
10. Previously documented allergy to ondansetron.

double blinded