What is the standard of care of a plaintiff in a medical malpractice action?

It is a fundamental legal principle that in an action for medical malpractice, the plaintiff must prove that the defendant physician failed to provide medical treatment in accordance with the accepted standards of care. (See ter Neuzen v. Korn 1995 CanLII 72 (SCC), [1995] 3 S.C.R. 674 at 693). The applicable standard of care is generally established through expert evidence. The plaintiff must prove via expert testimony that the defendant physician failed to possess or to exercise the reasonable degree of learning possessed by the average practitioner in his field.