Bacteriologic study of bile in 100 patients undergoing cholecystectomy for various manifestations of choletithiasis yielded 36 per cent positive cultures, with greater frequency in older individuals and those with acute cholecystitis and common duct stone; these results are comparable to those in previous studies and reaffirm the septicity of the bile. Incidence of wound infection, averanging 10 per cent in published series of cholecystectomies, was 0.5 per cent in 200 patients in whom a water-impermeable wound drape was sewn to the peritoneum to prevent contamination by potentially infected bile. This result, in patients with an infectious risk comparable to that in other series, establishes the value of meticulous wound isolation in preventing wound infection.