Allocation of liability for harm caused at least partially by AI or medical robot can be based upon a binary distinction. The binary is the distinction between substitutive and complementary automation. When AI and robotics substitutes for a physician, strict liability is more appropriate than standard negligence doctrine. When the same technology merely assists a professional, a less stringent standard is appropriate. Such standards will help ensure that the deployment of advanced medical technologies is accomplished in a way that complements extant professionals’ skills, while promoting patient safety.