Many antibiotics have been developed and used for the treatment of infectious diseases. Although they have been known to have various adverse eŠects, most of the mechanisms remain still unknown. New quinolones are well known to induce convulsions and their convulsant activity enhanced by concurrent administration of anti-in‰ammatory drugs. Each new quinolone has an individual convulsant activity with individual drug-interaction with anti-in‰ammatory drugs. And enoxacin, lome‰oxacin and gati‰oxacin have been reported to decrease blood glucose levels in a dose-dependent manner, but cipro‰oxacin and levo‰oxacin had no eŠect on the levels. It should be important to know the safety prole of antimicrobial agents before doctors administer these agents to the patients with infectious diseases.