In 1985, 100 episodes of klebsiella pneumoniae bacteremia in 98 patients were treated at the Veterans General Hospital--Taipei. The disease was community acquired in 58% and nosocomially acquired in 42%; unimicrobial in 86% and part of a polymicrobial bacteremia in 14%. Medical records of 90 episodes were available and were analyzed. Portals of entry, in decreasing order of frequency, were hepatobiliary (24%), respiratory (20%), and urinary tract (19%). Diabetes mellitus, which was found in 25 (28%) patients, was the most common underlying disease, followed by malignancies in 13 (14%), biliary tract abnormalities in 9 (10%), and cirrhosis of the liver in 8 (9%). The most frequent clinical findings were fever (89%) and leukocytosis (60%), followed by thrombocytopenia (27%), jaundice secondary to bacteremia (22%) and shock (21%). The course of one (1%) patient, who was diabetic and had a liver abscess, was complicated by metastatic septic endophthalmitis and meningitis. Overall case fatality was 46%. Poor prognostic factors included inappropriate antibiotic therapy, respiratory tract as a portal of entry and the presence of shock. Cephalosporins and aminoglycosides were the most active antibiotics. The use of one or more antibiotics, which included at least one cephalosporin, with in vitro activity against the corresponding isolate, with adequate dosage and an appropriate route of administration significantly reduced deaths directly attributed to K. pneumoniae septicemia, 32% (18/57), compared with 88% (21/24) in patients who were not treated appropriately (p less than 0.001). Combination therapy with a cephalosporin and aminoglycoside in conjunction with surgery in selected cases is the treatment of choice for K. pneumoniae bacteremia.