Clinical trials are the best way to find out if new treatments or vaccines work and how safe they are. If clinical trials show that a new treatment works and is safe, then it can be approved to be used by the people who need it. Clinical trials have led to a lot of important medical discoveries that help researchers find better ways to diagnose, prevent, and treat diseases. These medical discoveries can help people to live healthier, longer lives.

Clinical trials answer questions such as:

• Is a new drug or device safe?
• Is a new treatment better than existing treatments?
• Can a treatment help people with cancer?
• Does a treatment improve patients' quality of life?
• What is the best way to use a treatment?