Endoscopic retrograde cholangiopancreatography (ERCP) comes with a risk for post-ERCP pancreatitis (PEP), which accounts for considerable morbidity, high healthcare expenditure, and death. The pathophysiology of PEP and the underpinnings of the preventive effect of rectal NSAID (RN) is poorly understood. Guidelines advise to take preventive measures with a single dose of 100mg RN, peri-ERCP. While NSAID administration reduces the risk with 40%, PEP still occurs after ERCP. In addition, patients with a PEP history have a higher risk to develop recurrence after a subsequent ERCP. This might suggest that an underlying genetic risk may contribute to increasing the incidence of PEP in some patients.