Thirty-one patients with serious or complicated urinary tract infections were treated with oral enoxacin for between four and eight days. Twenty-five patients with microbiologically confirmed infections completed treatment with 400 mg enoxacin twice daily and at the end of treatment all urine cultures were negative. At short term follow-up, five to nine days after therapy, 21 of the 25 patients were still infection free. In total, reinfection or relapse occurred in 12 patients during the four to six weeks follow up period after termination of treatment. Significant side-effects (nausea and vomiting) occurred in only one patient.