A total of 125 ambulatory women (85 premenopausal and 40 postmenopausal) who experienced 174 acute urinary tract infections with mainly gram-negative bacteria (99%) was randomized to receive a single dose, 2-tablet treatment with either ofloxacin (400 mg.), norfloxacin (800 mg.) or ciprofloxacin (500 mg.). Cure was achieved in 163 of the 174 acute episodes (94%). More specifically, the cure rates were 97% (57 of 59 infections) with ofloxacin, 96.5% (56 of 58) with ciprofloxacin and 88% (50 of 57) with norfloxacin. While the initial cure rate of the acute urinary tract infections was 96% (112 of 117) in the premenopausal group, it reached only 90% (51 of 57) in the postmenopausal group. The 17 urinary tract infections that followed the initial 2-tablet quinolone treatment were cured by either an additional single dose, 2-tablet treatment with a different quinolone in 6 cases, a 1-day treatment with other adequate antibacterials in 9 and a 7-day treatment in 2. The 2-tablet quinolone treatment proved to be an effective, easy and cost-effective treatment for acute urinary tract infections in premenopausal and postmenopausal women.