What did the miasma theory attribute diseases to?

The miasma theory attributed diseases to "bad air" and environmental factors, specifically the belief that illness was caused by toxic vapors or "miasmas" emanating from decomposing organic matter, stagnant water, or poor sanitation. This theory dominated medical thought from antiquity through the 19th century, suggesting that these noxious fumes could enter the body through the respiratory system and lead to various ailments.

Understanding that the miasma theory was widely accepted before the germ theory of disease provides insight into historical public health practices, such as focusing on sanitation and improving environmental conditions to prevent illness. This emphasis on environmental influence reflects an early understanding of how conditions beyond individual control can affect health, paving the way for modern public health efforts aimed at addressing these factors.