Since the introduction of ciprofloxacin in 1987, fluoroquinolones have expanded far beyond their early role in the treatment of urinary tract infections. Clinical applications beyond genitourinary tract infections include upper and lower respiratory infections, gastrointestinal infections, gynecologic infec- tions, sexually transmitted diseases, and some skin and soft tissue infections. Their ease of administration, favorable pharmacokinetic properties, excellent tolerability, and efficacy give them enormous potential for use and misuse alike. Quinolones have few common adverse effects, most notably nausea, headache and dizziness. Less frequent but more serious adverse events include prolongation of the corrected QT interval, phototoxicity, liver enzyme abnor- malities, arthropathy, and cartilage and tendon abnormalities. While possess- ing many of the favorable properties of intravenous agents, most fluoro- quinolones offer the convenience of oral administration, thus contributing to decreased health-care costs through increased outpatient therapy and short- ened hospital stays. With the recent introduction of agents such as gatifloxacin and moxifloxacin, the traditional Gram-negative coverage of fluoroquinolones has been expanded to include Gram-positive organisms, most importantly Streptococcus pneumoniae.