Ofloxacin is a fluoroquinolone with activity against gram-positive and gram-negative aerobic and facultatively anaerobic bacteria, chlamydiae, and some related organisms, such as mycoplasmas or mycobacteria. It has been administered orally to 3,903 patients described in the New Drug Application (NDA) submitted to the U.S. Food and Drug Administration. Although some components of the NDA lack scientific rigor or fail to mimic clinical practice, other components and the collective whole identify important potential advantages and limitations of the new drug. Ofloxacin was effective in the treatment of infections of the skin, soft tissues, urinary tract, and lower respiratory tract as well as in that of gonococcal and nongonococcal urethritis and prostatitis due to sensitive organisms. Adverse reactions were relatively infrequent, generally mild, and usually self-limiting. Symptoms involving the gastrointestinal tract and the central nervous system predominated. The emergence of resistance and superinfections were uncommon. Few adverse drug interactions were encountered, although antacids may diminish gastrointestinal absorption. In certain defined clinical situations, ofloxacin appears to be a useful addition to the therapeutic armamentarium.