In a series of 78 patients with acute cholangitis, 48 were associated with common duct stones, and in 1/3 of these, the stones were believed to be primary common duct stones. Even though the clinical presentation of acute cholangitis can be nonspecific with a remarkable absence of physical signs, almost all patients had elevations of serum bilirubin, transaminase and alkaline phosphatase levels, an indication of disease of the biliary tree. Initially, all of the patients were treated with antibiotics and most responded rapidly. Escherichia coli and Klebsiella were the organisms involved in more than 85% of the 20 positive cultures, and penicillin and an aminoglycoside are recommended as the drugs of choice in acute cholangitis. Diagnostic procedures were then performed, and laparotomy was often not carried out for several days after admission. Of the 78 patients, 11 died. Of the 11 deaths in this series, 6 were from continuing or recurrent sepsis, and at postmortem examination, a retained stone or inadequately treated stricture was found. This points out the need for adequate diagnostic procedures prior to exploration.