This paper draws on letters in which patients or their relatives asked the famous Swiss physician Samuel Auguste Tissot (1728–1797) for medical advice. These letters, with their often very detailed accounts of previous encounters with physicians, illustrate the room that contemporary physicians gave to the patient's own experience and interpretation of illness. They also offer a vivid illustration of how the subjective perception of physical, mental, and emotional changes are profoundly influenced and shaped by prevailing medical concepts of the body and its diseases—in our case by various elements taken from humoral pathology and the new concept of “nervous diseases”. These ideas owed much of their appeal to notions of “sensibility” as a positive attribute of members of the upper class and to their fostering the belief that perfect health could be obtained by cultivating a restrained, “civilized” lifestyle. The patients’ attempts, in turn, to make sense of their disease—in some cases by drawing on Tissot's work on diseases stemming from masturbation—demonstrate that the creation of attractive explanatory models that hold the promise of control over the body and its diseases could serve as a powerful device, in line with Michel Foucault’s account of the “care of the self”, to propagate and enforce social and moral norms as seemingly dictated by human nature.