Miasma theory

Miasma theory also linked explanation to action. People carried flowers or strong-smelling herbs, or moved to the countryside to escape supposedly corrupted air. Their responses were not random: they followed logically from an incorrect understanding of disease.

The most widely accepted explanation was miasma theory: the idea that poisonous, foul-smelling air caused disease. Cholera often appeared in dirty neighbourhoods with open drains and accumulated waste, so the association between bad smells and illness seemed convincing.