Lomefloxacin, a difluorionated quinolone derivative, is a bacterial gyrase inhibitor, effective against gram positive and gram negative bacteria. Lomefloxacin interferes with bacterial DNA related processes like initiation, elongation and termination phases of replication, transcription, DNA repair, recombination, transposition, supercoiling and relaxation of DNA, resulting in a rapid killing of sensitive bacteria. Cross-resistance has only been reported with other quinolones, but not with any other group of antibiotics. No clinical studies are available about the efficacy in case infections with chlamydia.