Starting in the early 1950s, shortly after the founding of the People's Republic of China (PRC), the nascent socialist regime dispatched a huge number of Han Chinese health workers to the ethnic minority borderlands, in order to eradicate epidemic diseases, improve personal and public hygiene, and most crucially to curb the dreadful depopulation crisis reportedly taking place among the non-Han ethnic minority people. Usually referred to as ethnic hygiene (minzu weisheng), this ambitious public health project was believed as a remarkable achievement, not only having considerably bettered the wellbeing of ethnic minority groups, but also contributing to the consolidation of the PRC's rule in the geographical peripheral regions. Centering on the concept of ethnic hygiene, this research aims to explore the history of public health in the ethnic minority regions within the historical context of nation-state building in the founding years of the People's Republic. By closely examining the medical encounters between the Han Chinese medical practitioners and the ethnic minority patients, I will seek to investigate the following questions: How did the Han medical practitioners perceive the ethnic minority people before and after the medical expeditions? How did the indigenous people understand and take care of illnesses before the medical teams went there? How did their perception of the medical teams, the Han Chinese people in general, and the Communist regime change over the time? What happened when indigenous healing culture encountered modern biomedicine? In what ways did the indigenous people resist, accommodate, or appropriate the biomedical power carried by the Han medical teams? To what extent did the public health campaigns succeed in alleviating ethnic enmity? Viewing ethnic hygiene as a complex historical site, this project aims to shed light on the intertwined relations among hygienic modernity, nation-state building, and socialism in the early history of the PRC.