What is Res Ipsa Loquitur in California?

Res ipsa loquitur is a legal doctrine that allows a jury to presume negligence even where there is no direct evidence that proves who caused an accident or injury. When the evidence and facts would support a presumption of negligence, a jury may draw an inference that the defendant was a proximate cause of the accident and may be liable for any damages.

A jury can presume that an accident was caused by some negligent conduct by the defendant without direct evidence. This generally applies to personal injury lawsuits or medical malpractice lawsuits in California, where there may not be any direct evidence of who caused the injury.

If the jury finds the defendant was the proximate cause of the accident, the defendant may be liable for any damages caused by their actions. Damages in a personal injury lawsuit can include:

In this article, our California personal injury lawyers will discuss the following topics about “res ipsa loquitur” and presumed liability in personal injury lawsuits:

If you have further questions after reading this article, we invite you to contact us at Shouse Law Group.

Gavel stethoscope
Res ipsa loquitur is a legal doctrine that allows a jury to presume negligence even where there is no direct evidence that proves who caused an accident or injury.

1. What is “res ipsa loquitur?

The term res ipsa loquitur is Latin for “the thing speaks for itself." It was a legal doctrine created to bridge the gap in situations where someone was likely responsible for an accident but the injury victim cannot prove the necessary elements of negligence.

Under California law, when someone causes an accident and another person is injured, the person who caused the accident is generally liable for any damages. To prove negligence, the “plaintiff” has to prove the following:

  1. The defendant owed the victim a duty of care;
  2. The defendant breached that duty of care through negligence; and
  3. The defendant's negligence was a substantial factor in causing the victim's injuries.1

However, there may be some situations where the victim cannot prove all 3 elements of negligence but it is clear that the defendant was the one responsible for the accident.

Example: Stuart is walking down the street in downtown Los Angeles. Suddenly, Stuart is hit on the head by a piano falling from the sky and suffers a head injury. Stuart contacts a lawyer who investigates the accident.

Stuart's attorney finds out Mason was moving a piano into a high-rise apartment that day when the piano suddenly fell. Mason says he does not know what happened or how the piano fell.

Stuart may not be able to show Mason's negligence because no one knows how Mason breached his duty of care. However, one could infer that Mason did something that caused the piano to fall because he was the one who was handling the piano at the time. The accident speaks for itself. Unless Mason can show some other cause of the piano falling, Mason may be liable for Stuart's injuries.

1.1. The History of “res ipsa loquitur”

The history of res ipsa loquitur goes back to England in the 1800s. The doctrine was first applied to English tort law in the 1863 case of Byrne v. Boadle.2

Byrne was walking down the road when suddenly he lost consciousness and did not know what hit him. A witness testified that a barrel of flour fell out of a shop and hit Byrne on the head. The shop was owned by Boadle, but no one saw Boadle do anything to cause the accident.

The court found that the plaintiff could show that it was more likely than not that the accident was caused by negligence, even if the plaintiff could not prove all the elements of a negligence claim. A reasonable jury could find that it was more likely than not that the defendant's actions caused the accident.

Most jurisdictions in the United States have since adopted the doctrine of res ipsa loquitur, including California.

2. Who is responsible for an accident without direct evidence of fault?

In California, an injury victim can show the defendant was responsible for an accident through a number of ways, depending on the accident. In most situations, the plaintiff can claim damages by proving the defendant's negligence caused the accident, through a breach of the individual's duty of care to others.

Other ways of claiming liability include:

Negligence “per se” is another type of legal theory in which negligence can be presumed based upon a defendant's violation of a statute or ordinance. Violating a law or statute that results in an accident of the type for which the law is supposed to protect against can make the individual liable even if the elements of negligence are not met.3

Under California products liability laws, anyone who designs, manufactures or sells a defective product is strictly liable for injuries caused by that product, even if that person or company was not negligent. This includes design defects, manufacturing defects, or failure to warn.4

California's “premises liability” laws require people to keep property they own or occupy in a reasonably safe condition. The property owner or occupier who negligently failed to maintain their property may be liable for injuries caused by hazardous property conditions.5

2.1. Proximate Cause

Negligence in California generally requires showing that the defendant's actions were a proximate cause of the accident or injury. A proximate cause is a substantial factor in causing harm that a reasonable person would consider to have contributed to the accident. It does not have to be the only cause of the accident but it must be more than remote or trivial.6

Another way to think of proximate cause is, “but for” the defendant's actions, the plaintiff would not have been harmed.

With res ipsa loquitur, the jury can infer that the proximate cause of the accident was due to some negligent conduct by the defendant.

3. What are the elements of Res Ipsa Loquitur in California?

In California personal injury cases, the plaintiff must establish three things to invoke res ipsa loquitur:

  1. The accident or injury would not ordinarily have occurred without negligence,
  2. The thing or incident that caused the injury was under the defendant's exclusive control, and
  3. The harm was not due to anything the plaintiff did.7

3.1. Exclusive Control

The exclusive control element generally requires showing that the instrumentality or agent which caused the accident was under the exclusive control of the defendant. The control element is generally required to link the defendant to the probability that the accident was caused by negligence.

Exclusive control can be shared. For example, when a plaintiff sustains injuries while unconscious receiving medical treatment, all defendants who had any control over the plaintiff's body may have an inference of negligence under res ipsa loquitur.

Example: Joseph went in for an appendectomy. Joseph was given medication to knock him out during surgery. When Joseph awoke, he had a sharp pain in his neck and was unable to lift his arm.

Joseph filed a lawsuit alleging negligence against any of the doctors and nurses who were involved in the operation. Under res ipsa loquitur, all persons and instrumentalities exercising control over a person are liable for any unnecessary harm that results.

If the doctors and nurses involved in the surgery do not disclose who was negligent in harming Joseph, all of the defendants may share in the liability for Joseph's injuries.8

3.2. With Res Ipsa Loquitur, the Burden Shifts to the Defendant

When the plaintiff proves the necessary elements for res ipsa loquitur, it does not necessarily mean the defendant is ultimately liable. Res ipsa loquitur shifts the burden of evidence to the defendant. The defendant can still counter with evidence to show the lack of negligence or lack of proximate cause that the injury was caused by the defendant's negligence.9

Example: Lucy was walking through the farmer's market when an apple hit her in the head and she fell to the ground. At the apple stand, Johnny said he did not throw the apple and did not know where it came from. Lucy filed a claim against Johnny based on res ipsa loquitur.

Lucy's lawyer showed that an apple hitting someone in the head indoors is the kind of accident that does not normally occur in the absence of negligence. Johnny had the only stand that sold apples and had exclusive control of the apples. Lucy did not do anything to contribute to the accident.

Johnny could be liable for the injuries. However, Johnny testifies that it was his twin brother Franky who threw the apple and hid under the table. The burden shifted to Johnny but Johnny provided evidence that he was not the cause of the accident. Franky may then be liable for negligently throwing the apple and causing Lucy's injury.

4. Res Ipsa Loquitur in California Medical Malpractice Lawsuits

Res ipsa loquitur can be applied in medical malpractice lawsuits. Medical malpractice, also known as professional negligence, allows patients injured by healthcare professionals to sue for damages.

Under California law, medical malpractice lawsuits require a showing that:

  • A negligent act or omission by a health care provider,
  • In rendering professional services,
  • Which is the proximate cause of a personal injury or wrongful death, and
  • The services are within the scope of services for which the provider is licensed.10

However, in many medical situations, a patient may be injured while under a doctor's care and not know what caused the injury. This includes medical treatment like a surgery when the patient is unconscious. The patient does not know who caused the injury during surgery and can use res ipsa loquitur to shift the burden of proof onto the defendants.11

Medical malpractice res ipsa loquitur examples could include:

  • A patient suffers an infection after surgical sponge pieces are left in the body after surgery;
  • A patient dies because surgical scissors are left in the body after surgery;
  • A patient wakes up from surgery with burn injuries from a heating device; or
  • A patient comes out of surgery suffering nerve damage in an area unrelated to the surgery.
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For questions about res ipsa loquitur and negligence in California personal injury lawsuits or to discuss your case confidentially with one of our skilled personal injury attorneys, do not hesitate to contact us at Shouse Law Group.

We have local law offices in and around Los Angeles, San Diego, Orange County, Riverside, San Bernardino, Ventura, San Jose, Oakland, the San Francisco Bay area, and several nearby cities.


Legal References:

  1. California Civil Jury Instructions ("CACI") 400. See also California Civil Code section 1714(a) (“Everyone is responsible, not only for the result of his or her willful acts, but also for an injury occasioned to another by his or her want of ordinary care or skill in the management of his or her property or person.”)
  2. Byrne v. Boadle, 2 Hurl. & Colt. 722, 159 Eng. Rep. 299, 1863.
  3. California Evidence Code 669; California Civil Jury Instructions (CACI) 418(a); Spriesterbach v. Holland (2013) 215 Cal.App.4th 255.
  4. See, e.g., Soule v. GM Corp. (1994) 8 Cal.4th 548, 560 (“A manufacturer, distributor, or retailer is liable in tort if a defect in the manufacture or design of its product causes injury while the product is being used in a reasonably foreseeable way.”)
  5. California Civil Jury Instructions (CACI) 1001 (“A person who owns, leases, occupies, or controls property is negligent if he or she fails to use reasonable care to keep the property in a reasonably safe condition.”)
  6. California Civil Jury Instructions (CACI) 430.
  7. California Civil Jury Instructions (CACI) 417.
  8. Ybarra v. Spangard, 25 Cal.2d 486, 154 P.2d 687 (Cal.1944)
  9. California Evidence Code Section 646. (“(b) The judicial doctrine of res ipsa loquitur is a presumption affecting the burden of producing evidence.”). See also Howe v. Seven Forty Two Co., Inc. (2010) 189 Cal.App.4th 1155, 1163–1164.
  10. California Civil Code 3333.1(2); California Code of Civil Procedure 340.5(2).
  11. California Civil Jury Instructions ("CACI") 518.

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