The new quinolones have broad antimicrobial spectra covering all aerobic gram-negative and gram-positive bacteria encountered in urinary tract infections. All are administered orally, some also parenterally, low degree of resistance, few side effects and bacteriological and clinical cure rates similar to or higher than traditional antimicrobials make them especially suitable for treatment of complicated urinary tract infections including bacterial prostatitis. Non-critical use of quinolones in simple infections where standard drugs may be equally effective and safe should be discouraged.