Sixteen patients who had undergone cholecystectomy plus sphincteroplasty, 14 cholecystectomized patients and ten control patients were studied to evaluate whether differences existed in duodenogastric reflux and whether these were related to morphological damage of the gastric mucosa. Duodenogastric bile reflux during fasting was evaluated by measuring the concentration of total bile acids (by an enzymatic method) and single bile acids in the gastric juice by high performance liquid chromatography. The damage was evaluated histologically by systematic endoscopic biopsy of the antrum and body of the stomach. There was a statistically significant difference in fasting bile reflux between the three groups (Kruskal-Wallis test, P less than 0.001), and the group that underwent cholecystectomy plus sphincteroplasty had a significantly higher median value than the cholecystectomized group (P less than 0.05) and the control group (P less than 0.01). The distribution of chronic antral atrophic and superficial gastritis was different in the three groups (chi 2 test, P less than 0.005). Chronic atrophic gastritis was associated with cholecystectomy plus sphincteroplasty (P less than 0.01), while chronic superficial gastritis was more frequent in cholecystectomized patients. These results suggest that there may be more duodenogastric reflux after cholecystectomy plus sphincteroplasty than after cholecystectomy alone, and that there may be a correlation between the amount of duodenogastric reflux and the severity of mucosal damage.