miasma theory

miasma theory, historically, a widely accepted explanation of disease that attributed illness to exposure to harmful vapors, or miasmas, arising from decaying organic matter, stagnant water, sewage, refuse, and other sources of foul-smelling air. From antiquity through much of the 19th century, the theory shaped medical thought, public health policies, and urban planning in Europe, Asia, and other parts of the world. Although later disproven by advances in microbiology, miasma theory played an important role...