This dissertation examines the history of medical research in East Africa between 1940 and 1965, paying particular attention to the fine details of the research encounter, the transactional nature of medical research, and the multiple understandings of those participating in it. In the British colonies of Tanganyika, Kenya, and Uganda the 1940s signaled the beginning of regional medical research organizations that conducted large-scale projects involving tens of thousands of East Africans. These medical research encounters shaped the way many African participants responded to medical research, public health interventions, and illuminate research relationships today.

This research is based on newly discovered archival sources gathered in Mwanza and Amani, Tanzania at former colonial research stations, and extensive interviewing with medical researchers and research participants. The documents include the private papers of medical researchers in addition to confidential correspondences about some of the largest projects in the region. What emerges from these documents is a new perspective on the history of medical research.

I argue that large-scale research projects that ran during this period, such as lymphatic filariasis eradication attempts, malaria control experiments, the East African Medical Survey, and the Pare Taveta Malaria Scheme, offered few tangible benefits and exposed participants to both short and long-term risks. One of the constant sources of disagreement addressed by the dissertation is the different definitions of what constituted "risk," and researcher's inability to assess accurately what residents thought were risky activities. The case studies also make clear there was a broad array of opinions within the colonial establishment about how to handle difficult situations such as: when and how to end a project, and how to respond when conflict arose. Nearly all of the projects had moments of conflict; when residents felt they were participating in an inequitable exchange, problems ensued. This study has important implications for the region since East Africa is the site of a growing number of medical research projects, and conflict between researchers and subjects continues.