Because of excessive time involved in the development of antimicrobial drugs in Japan, bridging studies are gaining currency lately, which takes in foreign clinical study data. The Japanese Society of Chemotherapy (JSC)has set up the Bridging Study Committee to discuss the issue. The following is my report. Japanese classification of adaptable diseases is more comprehensive and makes fine distinctions compared with the Western one, which calls for some adjustment of disease groups and diagnoses between Japan and the West. In bridging studies foreign endpoints and evaluation periods should in Japan. Dosing method and amount are the toughest part of bridging. Provided PK and drug sensitivity of the casual bacterium are the same, the same dosing method and amount should be used. We will need a review of the standards of standard drugs used in the treatment of diseases under study or organisms and the definition of control drugs for our efficacy and safety study. As we get more experience in bridging studies, I think it will be increasingly important that we have more disucussions with JSC and regulatory authorities.