We want you to live a longer, healthier life. Through clinical trials, which involve people who volunteer to participate in them, researchers can better understand how to diagnose, treat and prevent diseases or conditions. Clinical trials help bridge research and patient care by evaluating therapies, drugs and diagnostic tools to drive discoveries into clinical practice. Clinical trials are different than medical care. When you visit your physician, he or she diagnoses and treats your current illness or condition. During clinical trials, researchers are trying to gather new knowledge that will help them improve medical care for people in the future.