Reform of the medical education in the early 20th century America caused many consequences in the various aspects of the medical fields as well as the improvement of the medical education itself such as the reinforcement of the laboratory training in the basic science courses and hospital instruction in the clinical courses. The reform brought about the direct or indirect elimination of the irregular sectarian practitioners and the minority groups such as black and women from the medical market place, established the concrete position of the regular physicians in the American society, reinforced the biomedical aspects which would become the general tendency in the 20th century Western medicine. And the author stressed that the reform was neither initiated nor invoked but just accelerated by the so-called Flexner Report of 1910, rather it had been performed through the processes of the interaction and struggle between the various contradictory trends, tendencies, and forces such as american Medical Association (AMA), some leading medical educators and scientists, medical colleges, and philanthropic foundations in the socio-cultural millieu gradually moving to favor the "science".