This is a randomized, double-blinded, controlled trial. This study is a head to head comparison of normal saline (NS) infusion versus Lactated Ringer's (LR) infusion in patients, with the primary outcome of post-ERCP pancreatitis occurrence. Patients will be randomized to either the NS infusion group or the LR infusion group. IVF will be started pre-procedurally and will be continued throughout the procedure. A IVF bolus will be given at the end of the procedure and then continued as a continuous infusion. Our null hypothesis is that there will be no significant difference in the rate of occurrence of post-ERCP pancreatitis between the infusion of LR and NS solutions. Our alternative hypothesis is that patients receiving LR solution infusion will experience a decreased rate of post-ERCP pancreatitis compared to patients receiving NS solution infusion.

Inclusion Criteria:

i. Possession of one of the following criteria which places the patient at high risk for post-ERCP pancreatitis and/or if patient is to undergo a planned endoscopic intervention deemed at high risk:

1. Suspicion of Oddi dysfunction
2. Personal history of post-ERCP pancreatitis
3. More than 8 cannulation attempts
4. Precut sphincterotomy
5. Endoscopic papillary balloon dilation of an intact sphincter
6. Endoscopic pancreatic duct sphincterotomy
7. Ampullectomy
8. Total bilirubin < 1.0

ii. Or possession of two or more of the following minor criteria:

1. Female sex
2. Age under 50 years
3. Personal history of recurrent acute pancreatitis
4. Pancreatic duct injection leading to "acinarization" or over 3 pancreatic duct injections
5. Pancreatic duct cytology acquisition

Exclusion Criteria:

1. Patients aged less than 18
2. Inability to provide informed consent
3. Pregnancy
4. Active acute pancreatitis
5. Any contraindication to aggressive IVF hydration: evidence of clinical volume overload (peripheral or pulmonary edema), respiratory compromise (oxygen saturation < 90% on room air), chronic kidney disease (creatinine clearance < 40 mL/min), systolic congestive heart failure (ejection fraction < 45%), cirrhosis, and severe electrolyte disturbance with sodium <130 mEq/L or >150 mEq/L
6. If patient does not undergo a planned high-risk intervention
7. If patient does not possess complete criteria which places them at high risk for post-ERCP pancreatitis
8. Patients with cholangitis
9. Patients with chronic and/or active pancreatitis
10. Patients with a true NSAID allergy
11. Patients greater than or equal to 75 years old