Health care information technology (HIT) vendors enjoy a contractual and legal structure that renders them virtually liability free—“hold harmless” is the term of art—even when their proprietary products may be implicated in adverse events involving patients. This contractual and legal device shifts liability and remedial burdens to physicians, nurses, hospitals, and clinics, even when these HIT users are strictly following vendor instructions. Vendors avoid liability by relying on the legal doctrine known as “learned intermediaries” and on warranties prohibiting claims against their own products' fitness. According to this doctrine and legal language, HIT vendors are not responsible for errors their systems introduce in patient treatment, because physicians, nurses, pharmacists, and health care technicians should be able to identify—and correct—any errors generated by software faults.