The elucidation of ancient concepts of health and sickness, and of culture-specific classifications of morbid conditions through ancient texts, poses multiple problems of interpretation. Searches for retrospective diagnoses to ancient descriptions of symptoms and diagnostic labels have been rightfully criticised as based on a flawed assumption that diseases as defined by Western biomedicine are universal and unchanging. This chapter argues instead that looking at the culturally distinct ways in which ancient Mesopotamian medical texts and specialists designate, classify and distinguish different morbid conditions will bring us closer to understanding Mesopotamian medicine as a culture-specific healing system. The chapter presents an outline of different aetiologies, types of diagnoses and patterns of naming morbid conditions encountered in Mesopotamian medical texts. The latter part of the contribution discusses tendencies and advances of local specialists to systematise their accumulated knowledge of types of diseases, diagnoses and corresponding therapies. Such tendencies are visible in multiple innovations and developments in first millennium BCE texts, such as the formation of serialised medical compendia, the rise of astro-medicine and the appearance of a physiological model grouping ailments that are associated with four internal organs.