How does animal testing help medicine?

The practice of animal testing dates back to the Greeks. Before applying surgical procedures to humans, animals were used to verify the method. Louis Pasteur induced anthrax in sheep proving his germ theory. Ivan Pavlov used dogs to demonstrate classical conditioning. Insulin was isolated in dogs. Antibiotics and a vaccine for leprosy was developed in armadillos. In 1996, Dolly the Sheep was the first mammal to be cloned.

Drug testing using animals became a significant part of the drug development process. To avoid new drugs from coming on the market and causing bad reactions, Congress passed a law in 1937 requiring the new drug to be tested on animals first.