Data from randomized, controlled trials are the usual gold standard for determining the safety and efficacy of therapies for clinical practice. In the United States, the U.S. Food and Drug Administration (FDA) reviews these trials in order to determine whether the drug is safe and effective. Have you ever wondered what data the FDA evaluate in determining the safety and efficacy of drugs? Have you ever wondered what constitutes the adequate and well-controlled trials that the FDA evaluate when making decisions? How does one quantify the uncertainty that still remains even after reviewing clinical trials? How does this apply to clinical practice? And why, as clinicians, should you care? This talk will explain the science behind the regulations by explaining the basic principles of clinical trials and a discussion of evaluating the overall risks and benefits of therapies, using issues with antimicrobial drugs as examples. This talk will explain how the appropriate design and analysis of clinical trials impacts clinical practice.