Ever since its description approximately 100 years ago, the sphincter of Oddi 
has been surrounded by controversy. First, whether it indeed existed, second, 
whether it had a significant physiological role in man and more recently whether 
abnormalities in its function give rise to a clinical syndrome. Data from animal 
and human studies, using sensitive techniques, have helped define the 
physiological role of the sphincter of Oddi, and more recent studies are 
determining the factors which control sphincter of Oddi function. These studies 
support Oddi's original description that the sphincter has a major role in the 
control of flow of bile and pancreatic juice into the duodenum, and equally 
importantly helps prevent the reflux of duodenal contents into the biliary and 
pancreatic ductal systems. The controversy of whether abnormalities in sphincter 
of Oddi motility result in clinical syndromes has not been totally resolved. 
Part of the difficulty has been inability to document normal and hence abnormal 
function of the sphincter. With the emergence of endoscopic biliary manometry as 
a sensitive and reproducible technique, however, the motility of the human 
sphincter of Oddi has come under closer scrutiny and allowed definition of 
possible disorders. We have used the term sphincter of Oddi dysfunction to 
define manometric abnormalities in patients who present with signs and symptoms 
consistent with a biliary or pancreatic ductal origin. Based on the manometry, 
we have subdivided the dysfunction into two groups; a group characterised by a 
stenotic pattern - that is, raised sphincter basal pressure - and a second group 
having a dyskinetic pattern - that is, paradoxical response to cholecystokinin 
injection, rapid contraction frequency, high percentage of retrograde 
contractions, or short periods of raised basal percentage of retrograde 
contractions, or short periods of raised basal pressure. It is apparent from the 
mamometry but also from the clinical data that the patients are a heterogeneous 
group and thus any therapy would need to be tailored for each patient and 
abnormality. The most recent therapeutic data suggest that patients with the 
stenotic pattern on manometry respond to division of the sphincter, however, 
those patients with the dyskinetic manometric pattern show no significant effect 
after sphincterotomy. Further prospective trials evaluating therapeutic options 
are under way and their results are eagerly awaited.