The pharmacokinetics of cefroxadine, a new orally active broad-spectrum cephalosporin, was studied in healthy volunteers and patients with impaired renal function after a single oral dose of 500 mg. The pharmacokinetic parameters of cefroxadine were obtained by analysing the serum level data of the drug based on a one-compartment open model. The mean serum half-life of cefroxadine was 0.97 h in healthy subjects, and was prolonged to 41.7 h in patients with a creatinine clearance of < 5 ml/min. There was a significant linear correlation (p < 0.001) between the elimination rate constant of the drug and the creatinine clearance. In healthy subjects, 71% of the administered dose was excreted in the urine collected over the first 6 h.