After intravenous administration of 1 g of cefpiramide, the biliary elimination of the drug was studied by using high-performance liquid chromatography. In five healthy volunteers, a mean peak concentration of 339 ± 107 (standard error of the mean) ,ug/ml was measured in aspirated duodenal fluid during h 2 after administration, and 1.2% of the dose given was recovered over a 4-h period. A maximal concentration of 1,161 ± 392 ,ug/ml was reached during h 2 in T-tube bile from 10 recently cholecystectomized patients, with a 24-h biliary recovery of 23.1%; urinary recovery over the same period averaged 49.4%. In 10 patients undergoing cholecystectomy, the concentrations in serum, choledochal bile, gallbladder bile, and gallbladder wall 1 h after cefpiramide administration were 157 ± 21, 1,726 ± 501, and 84 ± 33 ,ug/ml and 23 ± 4 ,ug/g, respectively. These figures represent the highest biliary concentrations attained so far with a beta-lactam antibiotic and are therefore a good prerequisite for treatment of biliary tract infections with cefpiramide.