Trends regarding symptomatic (pancreatitis, jaundice, cholangitis; 221 patients) and asymptomatic (detected at cholecystectomy; 333 patients) common bile duct stones were studied by comparing the period 1970-1978 with the period 1979-1986. There was a significant increase in the population-based incidence of symptomatic stones (8-20 cases/100,000 inhabitants/year) and a slight decrease in the rate of asymptomatic stones diagnosed at cholecystectomy (12-10 cases/100 cholecystectomies/year). The proportion of patients aged 70 years or more increased from 31 to 60% in the symptomatic group. The proportion of patients undergoing cholecystectomy with choledocholithotomy as the primary procedure decreased from 75 to 44%. During the second period, endoscopic sphincterotomy accounted for 81 % of all primary procedures among patients with symptomatic stones. The type of treatment disregarded, the frequency of clinically overt retained or recurrent stones increased from 7 to 22%. Overall, the frequency of general complications decreased from 9.1 to 4.5%, mainly due to a decrease in the symptomatic group. The frequency of procedure-related complications also decreased in the symptomatic group (25.4-14.9%), whereas it increased in the asymptomatic group (13.5-23.4%). The mortality rate decreased in both groups (symptomatic 14.9-5.2%, asymptomatic 3.4-1.3%). The total duration of stay in hospital decreased by 48% for patients with symptomatic stones and by 23% for those with asymptomatic stones. Possible explanations for these changes are discussed.