Mean peak enoxacin serum concentrations in nonfasted CF-1 mice following a single 50, 100, or 200 mg/kg oral dose were 2.0, 4.0 and 11.4 mg/l, respectively, with proportional increases in area under the serum concentration curves. Oral enoxacin was significantly more effective than tobramycin or dicloxacillin in experimental Pseudomonas aeruginosa and Staphylococcus aureus infections respectively. Enoxacin was as effective as tobramycin against P. cepacia and Escherichia coli infections. Enoxacin may be useful as an oral antimicrobial for the treatment of selected systemic bacterial infections.