The pharmacokinetics of enrofloxacin (EFL) and its active metabolite ciprofloxacin (CIP) was investigated in 7-8 month old turkeys (6 birds per sex). EFL was administered intravenously (i.v.) and orally (p.o.) at a dose 10 mg kg(-1) body weight. Blood was taken prior to and at 0.17, 0.33, 0.5, 1, 2, 3, 4, 6, 8, 10 and 24 h following drug administration. The concentrations of EFL and CIP in blood serum were determined by high-performance liquid chromatography (HPLC). Serum concentrations versus time were analysed by a noncompartmental analysis. The elimination half-live and the mean residence time of EFL after i.v. injection for the serum were after oral administration 6.64+/-0.90 h, 8.96+/-1.18 h and 6.92+/-0.97 h, 11.91+/-1.87 h, respectively. After single p.o. administration, EFL was absorbed slowly (MAT=2.76+/-0.48 h) with time to reach maximum serum concentrations of 6.33+/-2.54 h. Maximum serum concentrations was 1.23+/-0.30 microg mL(-1). Oral bioavailability for for EFL after oral administration was found to be 69.20+/-1.49%. The ratios C(max)/MIC and AUC(0 --> 24)/MIC were respectively from 161.23+/-5.9 h to 12.90+/-0.5 h for the pharmacodynamic predictor C(max)/MIC, and from 2153.44+/-66.6 h to 137.82+/-4.27 h for AUC(0 --> 24)/MIC, for the different clinically significant microorganisms, whose values for MIC varies from 0.008 microg L(-1) to 0.125 microg mL(-1).