A plaintiff in a products liability case asserts that the manufacturer of a product should be liable for personal injury or property damage that results from a defect in a product or from false representations made by the manufacturer of the product. A defendant often tries to disprove the plaintiff's case by showing that the product was not defective or that the plaintiff's misuse of the product was what caused harm to the plaintiff.

Products liability law consists of a mixture of tort law and contract law. Aspects of this area of law related to tort include strict liability, negligence, and deceit. Aspects that relate to contract law relate mostly to the laws governing warranties. Because this area of law is really hybrid in nature, a plaintiff may assert a number of possible claims, such as negligence, breach of implied warranty of fitness, breach of express warranty, or fraud.

The basis for products liability law developed over several centuries. English courts developed the doctrine of caveat emptor, meaning "let the buyer beware." Under this doctrine, a buyer was expected to protect himself against both obvious and hidden defects in a product and could not recover from the manufacturer for damages caused by these defects. Over time, however, English courts began to recognize a rule that a seller implicitly warrants that a product does not contain a hidden defect. On the other hand, American courts continued to employ the caveat emptor rule for most of the nineteenth century.

When courts in the United States began to impose implied warranties of merchantability in the late 1800s, the rule required that the plaintiff have privity of contract with the defendant. This meant that the buyer must have purchased a product directly from the manufacturer in order to recover from the manufacturer. During that time, manufacturers had begun to rely more heavily on retailers to sell products. Since many buyers did not actually purchase the products directly from the manufacturers, though, those buyers could not recover for breach of implied warranty from the manufacturers due to a lack of privity of contract.

Courts opened the doors to modern products liability cases in the 1950s and 1960s by allowing remote plaintiffs to recover against the manufacturers of defective products. The American Law Institute (ALI) included rules pertaining to products liability in the Restatement (Second) of Torts, which was officially promulgated in 1965. Since the 1960s, the law of products liability has continued to expand and develop. The ALI recognized this development by approving the Restatement (Third) of Torts: Products Liability, in 1998.