Why and how modern medicine began to develop in Colonial Taiwan﹖This is the main concern of Gotou Shinpei's practice and idea of medicine in the 1880's, characterized by social Darwinism and nationalism. For Meiji Japan, biological notions about the competition between species and the survival of the fittest were applied to support nationalism. It can be called social Darwinism. Gotou as a health officer applied biological notions to public health, and formed a theory of state hygiene. He assumed that the nation had to struggle for survival, therefore the ways to strengthen the health of an organic nation were important. To him, the best policy was to establish a scientific health management, in which a well-coordinated national health system, professional administrators, and local governments functioned together, respecting old customs and gradually adopting the new policy. From 1898 to 1906, when Gotou was the chief civilian administrator of the Colonial government, the had great responsibility and power to consolidate the colonial policies. He thought that modern medicine and the traditional pao-chia system were useful in controlling epidemics and endemics in Taiwan, and biological laws should be applied. Therefore, health institutions were established and modern medicine was notably expanded. In order to assist the Japanese to acclimate to the colonial environment, Gotou especially endeavored to establish a tropical medicine. Upon the foundation of modern medicine, the Colonial government manipulated police and the pao-chia system to push forward sanitary campaigns. To Colonial Taiwan, biological notions provided a justification for colonialism and imperialism. Theories in modern medicine seemed to support Japan as superior in the race struggle, thus consolidating the colonial regime and contributing to Japan's imperial expansion.