Eighty-nine college women with acute urinary tract infections were treated orally with either 1,000 mg of cefuroxime axetil in a single dose (n = 59) or 250 mg of cefaclor three times a day for 7 days (n = 30). At 1 week posttherapy, 88% of the patients in the cefuroxime axetil group and 97% in the cefaclor group were clinically and bacteriologically cured (P greater than 0.10). There was no statistically significant difference between the cure rates of the two treatment groups. However, this study has only a 50% power to detect a 10% difference. Therefore, there is a substantial possibility of a type II error, i.e., failing to find a difference that is actually present. At 4 weeks posttherapy, 78% of the patients in the cefuroxime group and 80% in the cefaclor group remained cured. By 36 weeks posttherapy, the cumulative rate of recurrence in both treatment groups was 60%. Of the patients with a positive antibody-coated bacteria test, fewer achieved a short-term cure after single-dose treatment with cefuroxime axetil than those with a negative antibody-coated bacteria test (67 versus 96%; P less than 0.01).