Colobronchial fistula: a rare complication of Crohn's colitis. A 29-yr-old white woman presented with chronic pneumonia in the left lower lobe and with left pleural effusion. She was known to have inflammatory bowel disease, but she was asymptomatic under maintenance treatment with 5-ASA. She received numerous antibiotic regimens according to susceptibility testing of microorganisms cultured from sputum and bronchial lavage and on an empiric basis was also given antituberculosis treatment, but there was no clinical improvement or change in the chest radiographic findings. Sputum was repeatedly examined and yielded, among other organisms, Clostridium inocuum, Enterobacter, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus aureus. On one microscopic examination of sputum, the presence of feculent material was suspected. A subsequent gastrografin enema revealed a cologastric and colobronchial fistula between the splenic flexture of the colon and the greater curve of the stomach and the bronchial system. Segmental resection of the colon and resection of the lower lobe of the left lung were performed. Histologic findings of the resected colon were consistent with Crohn's disease. After a long period of postoperative recovery, the patient returned to good general health and well-being. To our knowledge, a colobronchial fistula caused by Crohn's colitis has not been previously reported. 