In order to investigate the roles of quality requirements for antibiotic products in Japan, from historical and hygienic aspects, we examined and analyzed how technology and knowledge in the production and quality control of penicillin were introduced from the United States of America, applied, and further developed. Owing to the strong support of Colonel Crawford Sams, the chief of the Public Health and Welfare Section of the Supreme Commander for Allied Power/General Headquarters, via the Ministry of Welfare in Japan, the technology and knowledge were acquired from an experienced leader, Dr. Jackson W. Foster, and as a result, domestic production of penicillin was successfully achieved in amounts required to meet national demands sufficiently within three years in a devastated post-war-torn Japan. Based on the consensus that penicillin should be dealt with as “biological products” similar to vaccines and antisera, the quality standards for penicillin were enacted as the “Minimum Requirements for Penicillin (MRP)” on the 1st of May 1947. Due to the development of penicillin production technology, the quality standards of penicillin provided by the MRP were revised often to higher levels ; content of the active element from no less than 60 units/mg (purity 3.8%) to no less than 1,430 units/mg (purity 89.7%). Regarding the penicillin preparations, the content of the active ingredient per vial was changed from 30,000 units at the beginning, to 100,000 units in January 1948, to 3,000,000 units in December 1950, and two preparations containing 200,000 units and 1,000,000 units per vial are currently available, according to clinical convenience.