PROBLEM TO BE SOLVED: To search, in order to inhibit the emergence of levofloxacin-resistant strains, a levofloxacin ophthalmic solution capable of curing eye infections in a short period of time with a dose such that it never increases the rate of occurrence of side effects, compared with a conventional dose regimen or dosage of levofloxacin ophthalmic solution.SOLUTION: A drop of 1.5% (w/v) levofloxacin is administered to one eye three times a day. According to this invention, bacterial conjunctivitis is cured in a shorter period of time, compared with instillation of 0.5% (w/v) ophthalmic solution three times a day, which is a conventional dose regimen or dosage, without increasing the rate of occurrence of side effects. The tolerance enhancement of ocular infection-causative bacteria such as Staphylococcus aureus to levofloxacin, which results from the short-term use of the conventional dose regimen or dosage of levofloxacin ophthalmic solution, is directly suppressed.【課題】レボフロキサシン耐性菌の出現を阻止するために従来の用法または用量のレボフロキサシン点眼液よりも短期間で眼感染症を治癒し、且つ副作用の発現率も増大させない用量のレボフロキサシン点眼液を探索する。【解決手段】１．５％（ｗ／ｖ）の濃度のレボフロキサシンを、１眼あたり１滴、１日３回点眼する。【効果】従来の用法または用量である０．５％（ｗ／ｖ）点眼液の１日３回点眼よりも短期間で細菌性結膜炎を治癒し、しかも副作用の発現率も増大させない。従来の用法または用量のレボフロキサシン点眼液の短期使用を原因とする黄色ブドウ球菌等の眼感染症起炎菌の耐性化を直接的に抑制する。【選択図】図２
