During a 30-month period 73 patients underwent operation for choledocholithiasis. Thirty-three of these patients (45%) had cholangitis preoperatively. When compared to patients with common duct stones who had no preoperative cholangitis, patients with cholangitis were older (P less than 0.001), more likely to present with jaundice (P less than 0.01) and leukocytosis (P less than 0.01), and more likely to have retained or primary common duct stones (P less than 0.01). Cholangitis patients were also more likely to have bactibilia (P less than 0.025), and anaerobes were isolated from the bile of 27% of these patients (P less than 0.01). Twenty-nine of 33 cholangitis patients (88%) received a minimum of 4 days of broad-spectrum antibiotics including an aminoglycoside prior to operation (P less than 0.01). Despite these clear differences, patients with preoperative cholangitis were not more likely to develop infective sequelae or biliary complications. However, cholangitis patients were much more likely (P less than 0.001) to develop an increase in serum creatinine (33% versus 3%) which, in turn, contributed to a longer (P less than 0.01) postoperative hospitalization. Since therapy with aminoglycosides may have contributed to postoperative morbidity and prolonged hospital stay, aminoglycosides should be reserved only for patients with the most severe cholangitis and should be used with great caution.