A 64-yr-old woman with ERCP manometry proven papillary dysfunction is described. This patient responded to nitrate therapy with disappearance of the pain and decrease in both basal and phasic sphincter activity. It is suggested that nitrate administration should be used to distinguish between patients with functional and organic pathology of the sphincter of Oddi. Nitrate therapy should be tried in patients with papillary dysfunction and only if this fails, should endoscopic sphincterotomy be considered.