Oddi's sphincter motor activity was studied in 15 healthy subjects and 15 patients with recurrent pyogenic cholangitis. No significant difference was found in the common bile duct pressures, the Oddi's sphincter basal pressures or the amplitude, frequency and duration of phasic contractions between the controls and patients. However, a significant difference was found in the percentage of antegrade and retrograde phasic wave sequences between the two groups. In control patients 64.0% 2 5.3% of phasic wave sequences were antegrade, and 20% f 3.6% were retrograde. In patients with recurrent pyogenic cholangitis, 37% 2 3.6% of phasic wave sequences were antegrade, and 42% f 5.5% were retrograde. No significant difference was found in the percentage of simultaneous phasic wave sequences (16% f 1.5% vs. 18.6% & 2.8%, respectively) between the two groups. In all, five (33%) patients with recurrent pyogenic cholangitis had abnormal propagation of phasic contractions of Oddi's sphincter (retrograde phasic wave sequences greater than 50%), two (13%) patients had elevated Oddi's sphincter basal pressures (greater than 40 mm Hg) and one (7%) patient had increased frequency of Oddi's sphincter phasic contractions (more than 9imin). Six of the 15 patients had evidence of papillitis on duodenoscopy. We believe papillitis could induce motor abnormalities in these patients, thus resulting in delayed biliary drainage and recurrent attacks of cholangitis. (HEPATOLOGY 1993;17:53-58.) Recurrent pyogenic cholangitis (RPC) is a disease characterized by chronic infection and stone formation in the bile ducts (1). It appears as recurrent exacerbations and remissions of abdominal pain associated with jaundice, chills and fever. It mainly affects inhabitants of southeast Asia and is most prevalent in Taiwan and the south of China. In Hong Kong, it is the most common disease of the biliary tree and the third most frequent cause of acute abdominal pain requiring surgical intervention (2-7). The disease is being encountered with