How the world of experience, text-based medicine, and the social world came to interact with each other in a historically situated way is the subject of this doctoral thesis, which studies what I shall call zhang ("miasma") medicine in Song China (960-1279 CE). By the phrase "the world of experience," I refer to the bodily experience of the environment in a given region as well as to experiences of medical practices. "The social world" broadly refers to concomitant social, intellectual, and political events or trends. This thesis proposes a new approach to the study of the environment within the history of medicine in Imperial China (around 202 BCE-1911 CE), an approach which is inspired by anthropological analytical concepts. It highlights individuals' world of experience, treating their knowledge about environmental medicine as the culmination of a dynamic collaboration of their experiential world and existing culture-specific concepts, such as those deriving from scholarly medicine. This new approach dictates a re-examination of the sources that have received intensive attention in the history of medicine in Imperial China: texts up to the thirteenth century on the aetiology, therapies, and prevention methods of zhang as disorders endemic in Lingnan (in Guangdong and Guangxi provinces). Based on this re-examination, I contend that the Song period witnessed the emergence of a pronounced explanatory mode among authors of writings about zhang medicine about how their world of experience informed and affirmed their medical knowledge and practices relating to zhang. This Song explanatory mode embodies, I argue, the endeavor of Song scholar-officials and physicians to extend the proliferation of scholarly medicine at that time to zhang medicine, which lacked widely acknowledged textual references and therapies of medicinal effectiveness. The findings in this thesis firstly broaden our understanding of the development of environmental medicine in Imperial China and, secondly, extend our knowledge of the expansion of scholarly medicine into southern China in Song times.