When the Black Death struck Western Europe in late 1347, city dwellers across the region were already practising public health, in part by building, maintaining and monitoring infrastructures whose prophylactic value emerged from the experience of intensified urbanization. The demands of a new urban metabolism, evident from the twelfth century, prompted numerous cities, including Pistoia, to develop preventative health programmes in anticipation of and in response to diverse threats. The latter certainly included famine, floods, pestilence and war, but Pistoians and others were no less concerned by routine matters such as burials, food quality, travel and work safety, artisanal pollution and domestic waste disposal. All of these were recognized as impacting people’s health, based on the medical and natural-philosophical theories prevalent at the time, and their management took into consideration not only climactic conditions and multi-species behaviour, but also the smooth functioning of sites such as wells, canals, bridges and roads. The political value that municipalities and other stakeholders began to place on the upkeep of these sites exceeded their economic function and thus questions the seminal role that scholars tend to attribute to the second plague pandemic in public health history. It also demonstrates how a key aspect of Euro-American modernity continues to shape interpretations of urban and health histories and suggests a broader path for historicizing community prophylactics.