During the Italian campaigns of the French Revolutionary Wars (1796–1801), several epidemic outbreaks sparked acrimonious aetiological debates: were the fevers spread by soldiers and prisoners of war, or produced by environmental factors? This debate was not only a scientific issue, but also a political one, for causation was linked to accountability. Looking at a series of medical investigations written by French military practitioners, this paper argues that theories of contagion were used by civilians to accuse the army of spreading disease, (...) in what I describe as an “aetiology of blame.” Likewise, military officials attempted to absolve themselves of responsibility for the spread of disease by focusing on unwholesome environments, depicting diseases as unavoidable fatalities. Military doctors thus supported French imperial endeavours by obscuring the army's responsibility for the spread of diseases, putting forward aetiologies of fate and blaming individual behaviour. Even when they did not radically dismiss contagionist perspectives, military practitioners insisted on a wide range of pathogenic causes. Their discourses were in line with medical theories of the time, but they downplayed the responsibility of the army for the spread of diseases, which they depicted as a factor among others. Military doctors were thus not always involved in the direct and deliberate production of ignorance, but they did sustain controversies and uncertainty. (shrink)