The etiology of sphincter of Oddi dysfunction is usually due to local scarring secondary to gallstone removal or surgical manipulation or to inflammatory invasion from a nearby duodenal ulcer or suprapapillary pancreatitis. Whether or not primary papillary stenosis is present is controversial although the historical finding of adenitis is likely to be the cause.

The sphincter of Oddi is a smooth muscle valve that regulates the flow of bile and pancreas into the duodenum, first described by the Italian anatomist, Ruggero Oddi, in 1887. Sphincter of Oddi dysfunction (sphincter of Oddi D) is a broad term used to describe many disorders of the biliary, pancreatic, and hepatic systems that result from inappropriate contraction, tightening, and relaxation of this valve.