Women with culture-proven Chlamydia trachomatis cervical infection were randomized to receive either ofloxacin (300 mg) or doxycycline (100 mg), orally twice daily for 7 days. All 56 had negative cultures 5 to 9 days after treatment. Four weeks after treatment, 26 (93%) of 28 ofloxacin-treated patients and all 22 doxycycline-treated patients were cured. We conclude that 300 mg of ofloxacin given twice daily for 7 days provides effective therapy for chlamydial infection of the cervix.Mucopurulent cervicitis is among the most common sexually transmitted disease syndromes in women and can eventually lead to pelvic inflammatory disease, infertility, and obstetrical complications. It has not been as well studied as urethritis in men, but it is thought to have both similar prevalence and causes (3). As in male nongonococcal urethritis, Chlamydia trachomatis is the most common etiologic pathogen, causing as many as 50% of cases, whereas Neisseria gonorrhoeae is less common (3). Although tetracycline congeners and erythromycin are effective in eradicating C. trachomatis, they cause frequent side effects, must be taken two to four times daily, and are not reliably effective against N. gonorrhoeae. A single agent effective against both of these pathogens in women with mucopurulent cervicitis would be desirable for reasons of patient convenience and cost. The new fluoroquinolone antibiotics have excellent in vitro activity against both N. gonorrhoeae and C. trachomatis, and some have the potential for once-daily therapy (6). In particular, ofloxacin has been very effective in eradicating gonococcal infections and has been demonstrated in studies of men with urethritis and in small numbers of women with cervicitis to be as active against chlamydia as doxycycline (6). However, only small numbers of women were studied and posttreatment follow-up was no longer than 2 weeks in these studies. We report findings from a multicenter study comparing ofloxacin and doxycycline for treatment of chlamydial infection of the cervix with a follow-up visit 4 weeks after treatment.Data from four centers which took part in a multicenter study by using identical protocols were combined for this report Women were eligible for enrollment if they were between 18 and 65 years old, were not pregnant and using contraception, had received no systemic antimicrobial therapy within 30 days and no intravaginal antibacterial agent within 14 days prior to enrollment, had no allergy to carboxyquinolones or doxycycline, had no other significant medical illnesses, and had one or more of the following: 10 or more polymorphonuclear cells per high-power field (1,000 x) on a cervical gram stain, mucopurulent endocervical discharge, or a positive cervical culture for C. trachomatis. At enrollment, subjects underwent a medical history, physical examination, cervical gram stain, and culture for N. gonorrhoeae and C. trachomatis. Patients were then randomized to receive either ofloxacin (300 mg) or doxycycline hyclate (100 mg), orally twice daily for 7 days. Medicati...