In Fox v. Ethicon Endo-Surgery, Inc. (2005) 35 Cal.4th 797, the court addressed statutory time limitations, which prescribe the periods beyond which a plaintiff may not bring a cause of action. "There are several policies underlying such statutes. One purpose is to give defendants reasonable repose, thereby protecting parties from 'defending stale claims, where factual obscurity through the loss of time, memory or supporting documentation may present unfair handicaps.' A statute of limitations also stimulates plaintiffs to pursue their claims diligently. A countervailing factor, of course, is the policy favoring disposition of cases on the merits rather than on procedural grounds." (Id. at p. 806) Thus, a plaintiff who may be unaware of the specific facts establishing wrongful conduct may not delay action until discovery of detailed facts; that is a process for pretrial discovery. In Fox v. Ethicon Endo-Surgery, Inc., the plaintiff sued for personal injuries she sustained during an operation. Plaintiff's initial investigation only disclosed one kind of wrongdoing, namely medical malpractice. Later, after further investigation, the plaintiff discovered wrongful conduct of a wholly different sort, namely the distribution of a defective surgical stapler. (Fox, supra, 35 Cal.4th at p. 804.) Our Supreme Court held that the plaintiff should have been granted leave to amend her complaint to allege causes of action against the manufacturer of the stapler. (Id. at p. 811.) The plaintiff suffered complications after gastric bypass surgery, and filed a medical malpractice action against the doctor, treating hospital, and Doe defendants in a timely manner. Later, the doctor's deposition testimony revealed problems with the stapler used during the surgery, and the plaintiff filed an amended complaint asserting a products liability claim against the stapler manufacturer, Ethicon. Ethicon demurred, asserting the plaintiff's claims were barred by a one-year statute of limitations, and the plaintiff offered to file an amended complaint clarifying that she had no reason to suspect the stapler until after the doctor's deposition, and that no reasonable person would have suspected a defective stapler. On appeal to the California Supreme Court, Ethicon argued that a Court of Appeal holding in Bristol-Myers Squibb Co. v. Superior Court (1995) 32 Cal.App.4th 959, 965-966, established that once a plaintiff has knowledge or suspicion of negligence, the statute of limitations starts to run as to all defendants, regardless of the nature of the wrongdoing or cause of action. (Fox, supra, 35 Cal.4th at pp. 811-812.) The Supreme Court rejected that argument, concluding instead that when a plaintiff may only reasonably suspect one type of wrongdoing, the statute of limitations does not begin to run on a wholly different cause of action based on a different type of wrongdoing, the facts as to which the plaintiff may not yet be aware. (Id. at pp. 814-815.) In reaching its decision, the Supreme Court stated: "It is . . . consistent with our prior applications of the discovery rule to delay accrual of a products liability cause of action even when a related medical malpractice claim has already accrued, unless the plaintiff has reason to suspect that his or her injury resulted from a defective product. More broadly stated, if a plaintiff's reasonable and diligent investigation discloses only one kind of wrongdoing when the injury was actually caused by tortious conduct of a wholly different sort, the discovery rule postpones accrual of the statute of limitations on the newly discovered claim." (Fox, supra, 35 Cal.4th at p. 813.) In sum, the plaintiff filed a medical malpractice lawsuit after she had severe complications following gastric bypass surgery. During discovery, the plaintiff learned that a medical device used during surgery may have malfunctioned and caused her injury. (Fox, supra, 35 Cal.4th at p. 802.) At the time of the plaintiff's injury, a claim of products liability was subject to a one-year statute of limitations. The plaintiff timely filed her initial medical malpractice lawsuit, but she filed her first amended complaint adding a cause of action for products liability against the manufacturer of the medical device more than a year after her injury. (Id. at p. 809.) The manufacturer demurred to the amended complaint, arguing that the products liability claim was time-barred. In opposition, the plaintiff asserted she had no knowledge that the surgery involved the use of the medical device at issue, a stapler, and she also stated that she did not learn about the possibility of stapler malfunction until her attorney deposed the defendant doctor. (Fox, supra, 35 Cal.4th at p. 805.) The trial court sustained the demurrer without leave to amend. In doing so, the court relied on Bristol-Myers Squibb Co. v. Superior Court (1995) 32 Cal.App.4th 959, disapproved of in Fox at pages 803 and 805. The Court of Appeal reversed the trial court's order and instructed the trial court to grant the plaintiff leave to amend her complaint to allege facts explaining why she did not have reason to discover the factual basis of her products liability claim earlier. (Fox, supra, at p. 806.) "In so ruling, the Court of Appeal held that Bristol-Myers Squibb's 'bright-line rule of imputed simultaneous discovery of causes of action' did not apply." (Ibid.) The Supreme Court affirmed the appellate court's decision, agreeing that the plaintiff must be allowed to amend her complaint to plead facts supporting her claim that the discovery rule should apply in determining the timeliness of her products liability claim. (Fox, supra, 35 Cal.4th at p. 811.) The court noted the difference between a plaintiff's ignorance of the identity of a defendant and her ignorance of a generic element of a cause of action: "Although the identity of the manufacturer-wrongdoer is not an essential element of a products liability cause of action, and therefore ignorance of its identity will not delay the running of the statute of limitations citation, a plaintiff's ignorance of wrongdoing involving a product's defect will usually delay accrual because such wrongdoing is essential to that cause of action." (Id. at p. 813.) The court then held, "If a plaintiff's reasonable and diligent investigation discloses only one kind of wrongdoing when the injury was actually caused by tortious conduct of a wholly different sort, the discovery rule postpones accrual of the statute of limitations on the newly discovered claim." (Ibid.)