The treatment of cervical Chlamydia trachomatis infection in nonpregnant women was evaluated in a double-blind randomized study. Objective criteria were used to assess the response of cervicitis to therapy. Fifty patients were treated with tetracycline hydrochloride, 500 mg orally four times daily, and 50 patients were treated with rosaramicin, 250 mg orally four times daily, both for 7 days. Both agents were highly effective in eradicating C trachomatis. Both produced significant improvement in objective signs of cervicitis: eliminating mucopurulent endocervical discharge and edema of ectopy, and decreasing the clinical severity score of cervicitis. This trial shows that the 1-week course of tetracycline hydrochloride currently recommended for treatment of chlamydial urethritis in men is also highly effective for the treatment of chlamydial cervical infection in women. Rosaramicin, a macrolide antibiotic, was equally effective but produced a higher rate of gastrointestinal side effects.