Res ipsa loquitur means, roughly, “the thing speaks for itself.” Courts developed the concept of res ipsa loquitur to deal with cases in which the actual negligent act cannot be proved, but it is clear that the injury was caused by negligence. This doctrine was first recognized in the case of a man who was struck and severely injured by a barrel that rolled out of the second-story window of a warehouse. In the trial of the case, the defense attorney argued that the plaintiff did not know what events preceded the barrel rolling out of the window and thus could not prove that a warehouse employee was negligent. The plaintiff’s attorney countered that barrels do not normally roll out of warehouse windows. The mere fact that a barrel fell from the window was res ipsa loquitur; “it spoke for itself,” and it said that someone must have been negligent.

Most law students learn about res ipsa loquitur by reading a case about an airplane that disappears without a trace. There is no evidence of negligence, but there is a strong presumption that airplanes do not disappear without some negligence. In medical negligence cases, res ipsa loquitur can be invoked only when: (1) the patient suffers an injury that is not an expected complication of medical care; (2) the injury does not normally occur unless someone has been negligent; and (3) the defendant was responsible for the patient’s well-being at the time of the injury. For example, assume that a portable X ray is ordered in an intensive care unit on a young, otherwise healthy patient recovering from peritonitis. After the technician leaves, it is found that the patient has a dislocated shoulder. This is not an expected complication of an X ray; there are no explanations for the injury other than mishandling or failing to restrain the patient properly, and the defendant was responsible for the patient’s well-being at the time the injury occurred.

The strategic value of a res ipsa loquitur claim is that it does not require an expert to testify as to the proper standard of care. This has led plaintiffs to try to make res ipsa loquitur claims whenever they are unable to secure expert testimony to support their cases. Many states have limited the use of res ipsa loquitur in medical malpractice litigation, usually to claims such as a surgeon’s leaving a foreign body in the patient or operating on the wrong patient. In all other cases, the plaintiff must present expert testimony as to standard of care and its breach.