Scientists use animals to learn more about health problems that affect both humans and animals, and to assure the safety of new medical treatments. Medical researchers need to understand health problems before they can develop ways to treat them. Some diseases and health problems involve processes that can only be studied in a living organism. Animals are necessary to medical research when it is impractical or unethical to use humans. Animals make good research subjects for a variety of reasons.
Animals are biologically similar to humans.
However, the most important reason why animals are used is that it would be wrong to deliberately expose human beings to health risks in order to observe the course of a disease. Animals are used in research to develop drugs and medical procedures to treat diseases. Scientists may discover such drugs and procedures using alternative research methods that do not involve animals. If the new therapy seems promising, it is tested in animals to see whether it seems to be safe and effective. If the results of the animal studies are good, then human volunteers are asked to take part in a clinical trial.