To date no full-length treatment of the history of medicine in the British slave trade has been written. The historiographical domains of both fields remain largely separate. My dissertation fills this critical absence, by offering the first extended study of the social and cultural history of medicine in the eighteenth-century British slave trade, and the first analysis incorporating British and West African medical perspectives. I use a broad source base that includes medical treatises, pharmacopoeias, personal correspondence, merchants’ account books, and travel narratives. The project discusses the medical management and economics of the slave trade, the British and West African medical personnel who attended to the frequent morbidity crises, the circulation of British and West African medical knowledge and therapeutic traditions, and the seaborne medical encounters that occurred between doctors, mariners, and slaves. My dissertation argues that the fragile, transatlantic, medical world of the slave trade reshaped, altered, and at times undermined the medical knowledge, training, cultural understandings, and notions of health and healing that circulated in the eighteenth-century Atlantic world.