This article examines human experimentation under Japanese colonial rule, highlighting the practices by Japanese medical doctors at medical educational institutions in Manchuria in the years 1911-45. Although it proclaimed a civilizing mission in the colonies, colonial medicine exploited the bodies of the colonized for medical research and education. This article details unethical civilian practices which began well before the well-known, systematic atrocities of the Kwantung Army's Unit 731 in Manchuria. Bodies in the service of empire were long a part of the violent everyday life under colonial rule. The medical practices, experiments, and dissections carried out on the Chinese were more ethically problematic than those conducted in the home country. Over the period of colonial subjugation, such practices became steadily more radical. Colonial medicine, associated with physical experimentation, expropriated and endangered Chinese bodies. More importantly, the practices in medical colleges became the basis for Unit 731's human experimentation on Chinese using bacteriological and chemical weapons. The use of the human body is deeply intertwined with the interests of the power relations that governed the colony. This research shows how colonized bodies became material for the Japanese Empire.