Clinical trials are closely supervised by appropriate regulatory authorities. All studies that involve a medical or therapeutic intervention on patients must be approved by a supervising ethics committee before permission is granted to run the trial. The local ethics committee has discretion on how it will supervise noninterventional studies. In the U.S., this body is called the Institutional Review Board (IRB). Most IRBs are located at the local investigator's hospital or institution.

To be ethical, researchers must obtain the full and informed consent of participating human subjects. If the patient is unable to consent for themself, researchers can seek consent from the patient's legally authorized representative. Informed consent is clearly a necessary condition for ethical conduct but does not ensure ethical conduct. In some U.S. locations, the local IRB must certify researchers and their staff before they can conduct clinical trials. For instance, they must understand good clinical practice. International Conference of Harmonisation Guidelines for Good Clinical Practice (ICH GCP) is a set of standards used internationally for the conduct of clinical trials. The guidelines aim to ensure that the "rights, safety and well being of trial subjects are protected".

Benefits
Clinical trials that are well-designed and well-executed are the best approach for eligible participants to play an active role in their own health care, gain access to new research treatments before they are widely available, obtain expert medical care at leading health care facilities during the trial, and help others by contributing to medical research.

Risks
There are always certain risks or side effects to clinical trials. There may be unpleasant, serious or even life-threatening side effects to experimental treatment. The experimental treatment may not be effective for the participant. The protocol may require more of their time and attention than would a non-protocol treatment, including trips to the study site, more treatments, hospital stays or complex dosage requirements. Side effects are any undesired actions or effects of the experimental drug or treatment. Negative or adverse effects may include headache, nausea, hair loss, skin irritation, or other physical problems. Experimental treatments must be evaluated for both immediate and long-term side effects.