We made a bacteriological study of bile in a consecutive study of 210 patients studied in the General Surgery Department of the General Hospital of Elche (Spain) who underwent cholecystectomy for acute lithiasic cholecystitis, as a prognostic factor in the clinical evolution of these patients. The results obtained led us to the following conclusions. 1. The presence of positive bile culture is a risk factor predisposing to postoperative septic complications. 2. Bile cultures were more frequently positive in patients over 60-years-old. 3. In the early stages of the disease, positive cultures were more frequent. 4. The organism most often isolated was E. coli, so antibiotic treatment should be directed mainly against this agent.