As part of the Panel "Reason, ‘Science' and Anthropology - the Role of Early Christian Thought in a Perennial Debate", submitted by Karla Pollmann, the paper explores how Augustine could inform current debates in philosophy of medicine on whether diseases form a "natural kind" (a class of things sharing the same underlying nature) or not. The broad realist view says that they do, and the constructivist view says that they are social and cultural constructions. Daniel P. Sulmasy holds that diseases are not natural kinds though they are necessarily referred to the natural human kind, but neither are they social constructions. His view comes close to Augustine's own view on diseases as deficiencies within the corporeal substance. Though Augustine is not mentioned at all in these debates, I submit that he offers a viable "compromise" solution between the realist and constructivist views. Diseases are not essences, but neither are they inventions, abstractions: they are real, but not self-existent.