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HomeEvidence CodeDiv. 5Ch. 3Art. 3§ 646 Res Ipsa Loquitur Presumption

§ 646 Res Ipsa Loquitur Presumption

Evidence Code·California
AI Summary·Official Text·Key Terms·Related Statutes·References
AI SummaryVerified

§ 646 Res Ipsa Loquitur Presumption

Key Takeaways

  • •If something bad happens and it’s the kind of thing that usually doesn’t happen unless someone messed up, the court might assume the person in charge was careless.
  • •The person in charge can try to prove they weren’t careless or that their mistake didn’t cause the problem.
  • •The jury gets to decide if they believe the person in charge was careless based on all the facts.

Example

A surgeon leaves a sponge inside a patient during surgery.

This is something that usually doesn’t happen unless the surgeon or their team made a mistake. The court might assume the surgeon was careless, but the surgeon can try to prove they followed all the rules. The jury then decides if they think the surgeon was careless or not.

AI-generated — May contain errors. Not legal advice. Always verify source.

Official Source
View on CA.gov

§ 646 Res Ipsa Loquitur Presumption

(a) As used in this section, “defendant” includes any party against whom the res ipsa loquitur presumption operates. (b) The judicial doctrine of res ipsa loquitur is a presumption affecting the burden of producing evidence. (c) If the evidence, or facts otherwise established, would support a res ipsa loquitur presumption and the defendant has introduced evidence which would support a finding that he was not negligent or that any negligence on his part was not a proximate cause of the occurrence, the court may, and upon request shall, instruct the jury to the effect that: (1) If the facts which would give rise to res ipsa loquitur presumption are found or otherwise established, the jury may draw the inference from such facts that a proximate cause of the occurrence was some negligent conduct on the part of the defendant; and (2) The jury shall not find that a proximate cause of the occurrence was some negligent conduct on the part of the defendant unless the jury believes, after weighing all the evidence in the case and drawing such inferences therefrom as the jury believes are warranted, that it is more probable than not that the occurrence was caused by some negligent conduct on the part of the defendant. (Added by Stats. 1970, Ch. 69.)

Last verified: January 22, 2026

Key Terms

res ipsa loquiturdefendantpresumptionnegligent conductproximate cause

Related Statutes

  • § 647 Process Server Return Presumption
  • § 600 Presumptions And Inferences
  • § 601 Presumption Types And Effects
  • § 604 Presumption Burden Of Evidence
  • § 606 Presumption Burden Of Proof

References

  • Official text at leginfo.legislature.ca.gov
  • California Legislature. Evidence Code. Section 646.
View Official Source