AbstractNewly developed anti‐infective agents have been continuously supplied in the clinics of Japan over the past 50 years, and were beneficial in saving patients from life‐threatening infections. However, the emergence of resistant bacteria and uncommon pathogens has caused complications in chemotherapy. Further efforts have been made to develop newer and more effective agents to minimize such complications. The newest and the most effective agents are available even at primary‐care clinics, as the health insurance system allows the use of any agents approved by the government. Despite potential risks of the emergence and spread of resistant bacteria and the occurrence of adverse drug reactions, current usage of such effective agents shows more successful results, particularly in prognosis, than that of less effective ones. Because of the extreme changes in infectious diseases over the last 10–15 years, guidelines for the evaluation of anti‐infective agents have been proposed. It is essential to harmonize with the USA and the European guidelines for mutual acceptance of clinical data. However, it is true that practices of anti‐infective therapy in Japan, in the USA and in Europe are different both in dose regimen and assessments of efficacy and safety. As the leading country in the development of newer anti‐infective agents, Japan proposes the most sophisticated way to evaluate those agents to update knowledge in medical science.