A group of scientists, doctors, clergy, and patient advocates that reviews and approves the detailed plan for a clinical trial. IRBs are meant to protect the people who take part in a clinical trial. They check to see that the trial is well designed, legal, ethical, does not involve unneeded risks, and includes a safety plan for patients. There is an IRB at every health care facility that does clinical research, and every trial is reviewed by an IRB before the trial begins. Also called Institutional Review Board.