A major procedural complication in gastroenterology is post-endoscopic retrograde cholangiopancreatography (ERCP) acute pancreatitis. This occurs in 4–10% of patients undergoing ERCP. While the severity of post-ERCP pancreatitis is generally mild, up to 10% of cases may be severe and complicated by necrosis, multi-organ failure and even death.1 Prevention of this complication has proven only partially successful with patient selection and procedural measures contributing significantly to decreases in this complication. Although many pharmacological interventions have been used, few have demonstrated consistent or substantial benefits.1 A possible exception may be non-steroidal anti-inflammatory agents.2 In this issue of the journal, Noble and co-workers3 (see page 1566) surprisingly identify the pH of the contrast media used to opacify the pancreatic duct as a potential factor in post-ERCP pancreatitis.

Certain manipulations increase the risk of developing post-ERCP pancreatitis. These include sphincter of Oddi dysfunction, repeated attempts at cannulation, repeated contrast injection, and papillotomy. Each of these interventions can result in increased pressure within the pancreatic duct. Thus, the empirical use of temporary pancreatic duct stents to reduce intraductal pressure and prevent post-ERCP pancreatitis began about 15 years ago. The literature has consistently supported their use, particularly in reducing severe pancreatitis.4 The contributory role of contrast agents in post-ERCP pancreatitis has been explored. Osmolality was thought to be a causative factor, but the use of low osmolality contrast agents has not resulted in a lower incidence of post-ERCP pancreatitis.5 In this issue, Noble and co-workers explore a previously unexamined property of contrast media, its pH.

Noble describes a potentially important response to the contrast media …