The in-vitro activity of sparfloxacin against four pathogens commonly implicated in genital infections was compared with that of a number of other commonly administered antimicrobials. Sparfloxacin demonstrated excellent activity against Neisseria gonorrhoeae (MIC range of < or = 0.0002-5 mg/L for beta-lactamase producing strains, and < or = 0.0002-0.03 mg/L for non-beta-lactamase producing strains). This activity was similar to that of lomefloxacin and ciprofloxacin and was greater than that of ofloxacin. Sparfloxacin was more active against Ureaplasma urealyticum (MIC90 1 mg/L) than the other three quinolones (MIC90 4 mg/L). Sparfloxacin was much more active against Mycoplasma hominis (MIC90 0.06 mg/L) than the other quinolones (MIC90 1 mg/L). Sparfloxacin showed the most potent inhibitory and bactericidal activity of the quinolones against Chlamydia trachomatis with MIC and MBC of 0.06 mg/L (ofloxacin MIC and MBC 1 mg/L; ciprofloxacin and lomefloxacin MIC and MBC 2 mg/L). The results of this study and others performed by workers using different methods are consistently similar. Since sparfloxacin has broad activity against pathogens implicated in genital infections it may be a good therapeutic alternative for these syndromes.