Acute biliary diseases have become the most common indication for major abdominal surgery. We investigated 60 patients who underwent surgery for the acute biliary diseases, within 48 hours from the onset of the illness (group I), and over longer preoperative interval (48 h up to 5 days) (group II). Surgical specimen (gallbladder) was histologically examined. Samples for microbiological exams were obtained from gallbladder, common bile duct, Lund's node, gallbladder bed and peritoneal cavity. Positive bile cultures were found in 43% of group I, and in 70% of group II (p<0.05). Microbiological analysis revealed 13 different species, mostly Gram negative aerobic rods (69%). The incidence of bacteriobilia was in correlation with HP of lesions (79% in the acute and 18% in chronic lesions; p<0.01), what testified the importance of time interval and role of bacterial factor in the acute biliary pathology. Septic complications strictly occurred in patients with positive biliary findings. Early surgical treatment eliminates focus, and stops further development of intraabdominal and systemic septic complications. Correlation between bacteriobilia and septic sequelae calls for prophylactic use of antibiotics.