Ten patients with biliary-type pain, in whom investigations of the biliary tract were negative, are reported. All the patients were sexually active premenopausal women and all had evidence of infection with chlamydia trachomatis. Five patients submitted to laparoscopy had fibrinous adhesions between the anterior surface of the liver and the parietal peritoneum (perihepatitis). All 10 patients were diagnosed as suffering from the Curtis-Fitz-Hugh syndrome caused by Chlamydia trachomatis. The clinical similarities between the Curtis-Fitz-Hugh syndrome (right upper quadrant abdominal pain, perihepatitis and genital tract infection) and acute biliary disease are emphasized and the diagnostic implications discussed.