Quantitative cultures were made of jejunostomy fluid from 22 children with extrahepatic biliary atresia following hepatoportoenterostomy. Bacterial flora characteristics did not differ in patients with or without cholangitis. With the exception of Streptococcus group D, the most frequently encountered bacterial species with the highest mean concentrations in the jejunostomy fluid, were those mostly responsible for cholangitis (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa). In 19 of 22 acute episodes, the organism causing cholangitis identified in blood and/or liver was also isolated from jejunostomy fluid. However, quantitative determinations in this fluid did not permit reliable identification of this organism. When the same bacterium caused early relapse, it often persisted in the jejunostomy fluid.