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This month we are looking at Latin legal phrases that sound complicated but actually represent simple concepts.
One of our favorites is “res ipsa loquitur,” which means “the thing (or matter) speaks for itself.”
Pronounced RACE IP-sa LOCK-wit-tour, the doctrine is used to prove negligence with circumstantial evidence in tort (injury) cases. It allows a judge or jury to deduce negligence from the mere fact that an accident occurred when there is no other reasonable explanation.
Example: A small plane crashes into the ocean on a clear day. An inspection reveals no defective parts, birds in the engine, or other planes in the area. The plane’s only passenger was strapped into his seat and the pilot was not on the radio at the time of the accident. The logical explanation is that the pilot was negligent.*
To make use of res ipsa loquitur, the plaintiff must establish three things:
- The accident or injury would not ordinarily have occurred without negligence,
- The thing or incident that caused the injury was under the defendant’s exclusive control, and
- The harm was not due to anything the plaintiff did.
The burden then shifts to the defendant to prove that he or she was not responsible. If the defendant cannot do this, the plaintiff wins.

While the concept of res ipsa loquitur is simple, in practice the application can be tricky. For instance, sometimes it is clear that someone was negligent but the plaintiff cannot prove who it was.
Example: An otherwise healthy patient undergoes an emergency appendectomy. Afterward, the patient’s arm begins to hurt and then go numb. Eventually the arm becomes paralyzed.It is fairly obvious that someone on the surgical team was negligent. But because the patient was unconscious when the harm occurred, the patient cannot say who was responsible.^
The California Supreme Court has held that plaintiffs in this situation can still make use of res ipsa loquitur. All members of a surgical team share control for a patient’s well-being.
Therefore, the burden is on them rather than the plaintiff to explain what went wrong. This prevents the situation in which members of a group avoid liability by staying silent.
But remember — the doctrine of res ipsa loquitur simply shifts the burden of proof to the defendant. Innocent defendants can still avoid liability by:
- Identifying the wrongdoer, or
- Showing that they did not have control of anything that could have harmed the patient.
For instance, a nurse might be able to testify that orderlies dropped the patient while transferring the patient to the operating table. Or the nurse might be able to show that it was the nurse’s responsibility to watch the surgeon and not the patient.
Medical malpractice and vehicle accidents are common types of cases in which plaintiffs plead res ipsa loquitur in California. But the doctrine can be used in any type of injury case including (but not limited to):
Products Liability.
Example: The California Supreme Court held that a Coca-Cola bottling plant could be held liable for injuries after a bottle of soda exploded when someone opened it.**
Product maintenance.
Example: The California Supreme Court held that a cocktail lounge could be held liable for a patron’s injuries when the stool he was sitting on broke. (The patron had not been served any alcohol).^^
Fires or floods.
Example: An auto repair garage was presumed liable for property damage from a fire after it stored automobiles with full tanks of gas within 20 feet of an unvented gas heater.***
If you have any questions or would like more information, we invite you to call our California personal injury lawyers.
^ Ybarra v. Spangard, 25 Cal.2d 486 (1944).
** Zentz v. Coca Cola Bottling Co. of Fresno, 39 Cal.2d 436 (1952).
^^ Rose v. Melody Lane of Wilshire, 39 Cal.2d 481 (1952).
*** Horner v. Barber, 229 Cal. App. 2d 829 (1964).