Unavoidably unsafe products refer to exceptions in product liability law. If a product is found to be unavoidably unsafe, the manufacturer, distributor, or seller may not be liable for harm or damages that result from use of the product; the product is not considered defective. The product is not necessarily dangerous, but it cannot be made entirely safe for ordinary usage. Courts use four criteria to determine if a product is unavoidably unsafe or whether it is simply defective:

Manufacturing: Errors in the manufacturing process mean that the product is defective, not unavoidably unsafe. Impurities in ingredients, however, may be an exception to this rule. This exception relates primarily to blood products that may be tainted.

Warnings and Instruction: Consumers must be warned of all hidden damages related to the use of a product, as well as receive instruction in its safe and proper use. Furthermore, warnings must be clear, precise, and placed where they can easily be seen. Failure to provide proper warning and instructions means that the product is likely defective, not unavoidably unsafe.

Use vs. Risk: The dangers associated with the use of the product must not outweigh the benefits of use. To use an extreme and obvious example, a product that cures baldness but causes cancer in most users would probably not be considered unavoidably unsafe. The use of the product does not need to be a life-saving benefit; for example, many cosmetic products have been found to have a use that warrants the risk of their use.

Alternatives: The court must determine that there is no way to provide a similarly beneficial product that would pose lesser risk. The existence of an alternative may mean that the product is defective, not unavoidably unsafe. When examining the possibility of an alternative, courts will examine its viability, cost, safety, and benefits, both on its own merits and relative to the original product.

While the most common unavoidably unsafe products are prescription drugs, other possible products include medical devices, vaccines, blood products, cleaning compounds, cosmetic products, and firearms.