THIS STUDY is a review of the records of 20 patients in whom the diagnosis of pyogenic hepatic abscess was made at the Lahey Clinic in the years 1923 to 1966. In all patients the diagnosis of pus in the liver has been made at operation or at autopsy. Despite this we agree with Ochsner,1 and Rothenberg and Linder2 that there are patients who undoubtedly develop hepatic abscesses associated with cholangitis, but never come to operation or autopsy, and in whom the diagnosis is missed. Our current practice is to culture the bile at operation, and by the results of the sensitivity tests choose the antibiotic to be administered for any suspected postoperative cholangitis. This makes the definite diagnosis of small multiple abscesses even more difficult. All cases of amebic abscesses have been excluded from this review. Etiology Incidence.—The age of the patients at the time of