The "sudden emergency doctrine" (also called the "doctrine of imminent peril," the "doctrine of suddent peril," the "rule of sudden peril" and the "emergency doctrine") states that in the absence of antecedent negligence, a person confronted with a sudden emergency that deprives him of time to contemplate the best reaction cannot be held to the same standard of care and accuracy of choice as one who has time to deliberate. See Jeffrey F. Ghent, Annotation, Modern Status of Sudden Emergency Doctrine, 10 A.L.R.5th 680, 687 (1993). The doctrine has its origins in English law. See Jones v. Boyce, 171 Eng. Rep. 540 (N.P. 1816), holding it was reasonable for the claimant to jump out of a carriage which looked like it was about to crash, and sue for injury, even though the carriage did not crash.

In the area of dog bite law, the sudden emergency doctrine is used by bite victims who are injured in the course of defending their own dogs from attack, even though it is a natural human reaction -- and therefore not negligent -- to save a dog from imminent injury or death, as opposed to standing by and doing nothing. Indeed, the law of every state makes it a crime to merely be present at an organized dog fight, underscoring the repugnance that we have toward watching a dog sustain injuries. Nevertheless, the sudden emergency doctrine is often cited by plaintiffs to dispel any notion that rescuing their pet was inviting injury to themselves. 

The Restatement (Second) of Torts § 296 (1965), discusses “emergency” as follows:

(1) In determining whether conduct is negligent toward another, the fact that the actor is confronted with a sudden emergency which requires rapid decision is a factor in determining the reasonable character of his choice of action.
(2) The fact that the actor is not negligent after the emergency has arisen does not preclude his liability for his tortious conduct which had produced the emergency.

“[A] person who, without negligence on his part, is suddenly and unexpectedly confronted with peril, arising from either the actual presence, or the appearance, of imminent danger to himself or to others, is not expected nor required to use the same judgment and prudence that is required of him in the exercise of ordinary care in calmer and more deliberate moments.” (Leo v. Dunham (1953) 41 Cal.2d 712, 714.)

The “doctrine is properly applied only in cases where an unexpected physical danger is so suddenly presented as to deprive the injured party [or the defendant] of his power of using reasonable judgment.” (Sadoian v. Modesto Refrigerating Co. (1958) 157 Cal.App.2d 266, 274.) The exigent nature of the circumstances effectively lowers the standard of care: “ ‘The test is whether the actor took one of the courses of action which a standard man in that emergency might have taken, and such a course is not negligent even though it led to an injury which might have been prevented by adopting an alternative course of action.’ [Citation.]” (Schultz v. Mathias (1970) 3 Cal.App.3d 904, 912–913.)

The doctrine applies when a person perceives danger to himself or herself as well as when he or she perceives a danger to others. (Damele v. Mack Trucks, Inc. (1990) 219 Cal.App.3d 29, 36.) “[T]he mere appearance of an imminent peril to others—not an actual imminent peril—is all that is required.” (Damele, supra, 219 Cal.App.3d at p. 37.)

The doctrine of imminent peril may be used by either the plaintiff or the defendant, or, in a proper case, both. (Smith v. Johe (1957) 154 Cal.App.2d 508, 511–512.)

"Whether the conditions for application of the imminent peril doctrine exist is itself a question of fact to be submitted to the jury.” (Damele, supra, 219 Cal.App.3d at p. 37; see also Leo, supra, 41 Cal.2d at p. 715.)