Clinical research or clinical study is a scientific study of how a new medicine or treatment works in people. Through clinical studies, doctors find new and better ways to prevent, detect, diagnose, control, and treat illnesses.

Many new medicines and treatments are found to be helpful and safe in test tubes and in animals. They must also prove safe and effective in humans before doctors can prescribe them. This testing in humans is permitted only if that person volunteers for participation and understands the risks and benefits of taking part in a study.