Answer
Koch's postulates are a set of four criteria that establish a causal relationship between a microbe and a disease. The postulates state that the microbe must be present in all cases of the disease, it must be isolated and grown in pure culture, the pure culture must cause the disease when inoculated into a healthy host, and the same microbe must be re-isolated from the diseased host.
This concept is important in medical science because it provides a framework for identifying the cause of infectious diseases and developing effective treatments. By following Koch's postulates, scientists can determine whether a microbe is responsible for a particular disease and develop targeted therapies to combat it. Additionally, the postulates help to ensure that the causative agent of a disease is accurately identified, which is critical for preventing the spread of infectious diseases and protecting public health.