Pasteur's Germ Theory

Pasteur's Germ Theory states that many diseases are caused by microorganisms—tiny living germs like bacteria and viruses—that invade the body. Pasteur showed that these microorganisms can be found in the environment and can lead to illness if they enter our bodies. He demonstrated that diseases are not caused by miasma or "bad air," but by specific germs, and that heating (like pasteurization) can kill these harmful microorganisms. This discovery revolutionized medicine, leading to better hygiene, sterilization, vaccines, and treatments to prevent and control many diseases.