Miasma Theory

Miasma Theory was a historical belief that diseases were caused by "bad air" or noxious vapors, often emanating from decaying material or poor sanitation. It suggested that filth and foul smells spread illness. This theory dominated medical understanding until the late 19th century, when germ theory emerged, showing that microorganisms were the actual cause of many diseases. Miasma Theory influenced public health efforts, leading to improved sanitation and urban planning, even if it was based on incorrect assumptions about disease transmission.