John Donne's Language of Disease reveals the influence of medical knowledge -- a rapidly changing field in early modern England -- on Donne's thinking and writing. This knowledge played a crucial role in shaping how Donne understood his everyday experiences, and how he conveyed those experiences in his work. Examining a wide range of his texts through the lens of medical history, this study contends that Donne was both a product of his period and a remarkable exception to it. He used medical language in unexpected and striking ways that made his ideas resonate with his original audience, and that can illuminate his ideas for readers today.