[1] The plaintiff first assigns as error the Court of Appeals’ holding that the trial court properly instructed the jury that it could consider the relative percentage chance of paralysis in *269determining whether Dr. Ellis had the duty to inform the plaintiff of the risk of paralysis when all of the medical expert testimony indicated that Dr. Ellis did have such a duty.1
*270A physician or surgeon who undertakes to render professional services must possess the degree of professional learning, skill and ability which others similarly situated ordinarily possess; he must exercise reasonable care and diligence in the application of his knowledge and skill to the patient’s case; and he must use his best judgment in the treatment and care of his patient. Hunt v. Bradshaw, 242 N.C. 517, 88 S.E. 2d 762 (1955). He is held to the standard of professional competence and care customary in similar communities among physicians engaged in his field of practice. Dickens v. Everhart, 284 N.C. 95, 199 S.E. 2d 440 (1973).
Adherence to a minimal standard of care ordinarily requires a physician or surgeon to secure consent of an individual before providing him treatment. Consent to a proposed medical procedure is meaningless if given without adequate information and understanding of the risks involved. Therefore, the standard of professional competence prescribes that a physician or surgeon properly apprise a potential patient of the risks of a particular treatment before obtaining his consent.
The seminal case requiring a physician to obtain his patient’s “informed consent” is Salgo v. Leland Stanford, Jr. University Board of Trustees, 154 Cal. App. 2d 560, 317 P. 2d 170 (1957). There the court held that a physician “violates his duty to his patient and subjects himself to liability if he withholds any facts which are necessary to form the basis of an intelligent consent by the patient to the proposed treatment.” Id. at 578, 317 P. 2d at 181.
A major issue in informed consent cases is whether a plaintiff must present expert medical testimony to establish the existence and scope of a physician’s duty to disclose risks of a proposed treatment. See Annot., 52 A.L.R. 3d 1084 (1973). The Court of Appeals apparently proceeded under the theory that such testimony is not required when it concluded that, “We believe with this information [the mathematical probability of paralysis resulting from an arteriogram] laymen are capable of determining whether good medical practice requires a physician to inform his patient of the possibility of paralysis as a result of an arteriogram.” 53 N.C. App. at 479, 281 S.E. 2d at 96. The determination of this issue is not essential to the resolution of this case; therefore, we express no opinion as to the merits of the Court of Appeals’ sub silentio decision.
*271The question of the necessity of expert testimony need not be reached in this case because seven medical experts in fact expressed their opinions on the duty to advise a patient of the risk of paralysis in an arteriogram procedure. These witnesses, experts in the fields of neurology, neurological surgery, or radiology, all testified that the standard of good medical practice in Buncombe County in March, 1975 would be met by explaining to an arteriogram patient the risks of paralysis. Three witnesses, including the defendant Dr. Ellis, testified that failure to advise of the risks of paralysis would not conform to such standards of medical practice. No witnesses testified that failure to advise of the risks of paralysis was consistent with good medical practice in Buncombe County in March, 1975.
The expert medical witnesses based their opinions, in part, on evidence of the incidence of paralysis resulting from arteriogram procedures. Defendant contends, and the Court of Appeals held, that the chance of paralysis, approximately 1 in 500, in itself was evidence from which a jury could determine whether good medical practice required advisal of the risk. We disagree. Evidence of the remoteness of a particular risk, mathematically expressed as a ratio or percentage, is not sufficient, standing alone, to permit a jury to establish independently a standard of care for advisal of that risk in the face of uncontroverted expert medical testimony as to the existence and scope of the physician’s duty. Cf. Starnes v. Taylor, 272 N.C. 386, 158 S.E. 2d 339 (1968) (remoteness of the risk considered in the absence of expert medical testimony as to the proper standard).
The trial court therefore erred in instructing the jury to consider the remoteness of the risk of paralysis and to determine whether relating such a risk was required under the standard of medical practice in the professions of neurology and neuroradiology in March, 1975 in Asheville or similar communities. The uncontroverted evidence indicated that the standard of care required advisal of the risk of paralysis. “When all the evidence offered suffices, if true, to establish the controverted fact, the court may give a peremptory instruction — that is, if the jury find the facts to be as all the evidence tends to show, it will answer the inquiry in an indicated manner.” Chisholm v. Hall, 255 N.C. 374, 376, 121 S.E. 2d 726, 728 (1961). The trial court should have instructed the jury that if it found that the standard of *272medical practice in the professions of neurology and neuroradiology in March, 1975 in Asheville or similar communities required that an individual undergoing an arteriogram be advised of the risk of paralysis, as all the evidence tended to show, failure to adhere to that standard would result in civil liability.
[2] The plaintiff next assigns as error the instructions of the trial court that if the jury found that the referring neurologist Dr. Ledbetter had the sole responsibility of informing plaintiff of the risk of paralysis, then they should find Dr. Ellis not liable to the plaintiff. The instruction was not supported by the evidence. No witness testified that Dr. Ledbetter had the sole responsibility of advising plaintiff of the risks. It was at most his primary responsibility. The uncontroverted evidence tended to show, if the jury chose to believe it, that Dr. Ellis had a duty to explain the risks of paralysis to a prospective arteriogram subject. Therefore, the trial court erred in instructing the jury that it could find that the responsibility of informing the plaintiff was solely that of Dr. Ledbetter.
[3] The plaintiffs third assignment of error stems from the trial court’s instruction that if the jury found Dr. Ellis had not properly informed the plaintiff of the risk of paralysis, she still would not be entitled to recover if they also found that, had she been so informed, she would nevertheless have consented to the arteriogram. A requisite of a cause of action for negligence is that the alleged negligent act or omission by the defendant be the proximate cause of the injury. Meyer v. McCarley & Co., Inc., 288 N.C. 62, 215 S.E. 2d 583 (1975). If the plaintiff would have consented even after being apprised of all the facts, the failure to inform her was not a cause in fact of her undergoing the operation, and was thus not a cause of her injury. Therefore, the jury was properly instructed that it should consider what her decision would have been had she been properly informed of the risk of paralysis.
A major issue in informed consent cases is what standard to use in determining proximate causation. Note, Informed Consent — A Proposed Standard for Medical Disclosure, 48 N.Y.U.L. REV. 548 (1973). A subjective standard requires the jury to determine whether, if informed, this particular patient would have foregone treatment. Id. at 550. An objective standard requires the *273jury to determine whether, if informed, a reasonable, prudent person under all the surrounding circumstances would have foregone treatment. Id.
The problem with a subjective standard is that the only evidence usually available is the plaintiffs bald assertion, tempered by hindsight, as to what he would have done had he known all the facts. The apparent inequity of a jury basing its decision solely on such testimony has troubled courts, once even to the extreme of excluding the plaintiffs testimony on this issue. Watson v. Clutts, 262 N.C. 153, 160-61, 136 S.E. 2d 617, 622 (1964).
The detriments of the objective standard are more severe, however.2 In determining liability by whether a reasonable person would have submitted to treatment had he known of the risk that the defendant failed to relate, no consideration is given to the peculiar quirks and idiosyncracies of the individual. His supposedly inviolable right to decide for himself what is to be done with his body is made subject to a standard set by others. The right to base one’s consent on proper information is effectively vitiated for those with fears, apprehensions, religious beliefs, or superstitions outside the mainstream of society.
Therefore, we hold that the subjective test is the proper standard to apply in determining whether a patient would have undergone treatment had he known of the risks the physician neglected to related to him. To the extent that Watson v. Clutts, 262 N.C. 153, 136 S.E. 2d 617 (1964) conflicts with this decision by requiring exclusion of a patient’s testimony as to what he would have done had he known of the risks, that case is disapproved. The trial court properly instructed the jury that it should consider whether Ms. McPherson would have undergone the arterio-gram had she known of the risk of paralysis.
Remanded to the Court of Appeals for further remand to Buncombe Superior Court for a
New trial.