When something goes wrong in a medical setting, the instinctive reaction is often to assume fault. Roman law, however, has long warned against that reflex. The principle incumbit probatio qui dicit, non qui negat reminds us that the burden of proof rests on the person who makes the allegation, not on the one who denies it.
That principle was central to the Western Cape High Court’s decision in M.L v Van Der Merwe, a judgment that offers a timely reminder of how cautiously South African courts approach claims of medical negligence.
Unlike some delictual matters where the doctrine of res ipsa loquitur may assist a claimant, courts remain restrained when asked to infer negligence from outcome alone in medical cases. An adverse result, even a serious one, does not automatically justify a conclusion that a practitioner acted negligently.
In M.L v Van Der Merwe, the plaintiff underwent a laparoscopic procedure performed by a specialist gynaecologist and obstetrician. During the operation, a perforation occurred in the dome of the plaintiff’s bladder. Litigation followed on the basis that such an injury must have resulted from negligent surgical technique.
That assumption proved fatal to the claim. Despite expert evidence being led, the plaintiff was unable to demonstrate that the injury arose from conduct falling below the accepted standard of care. On the evidence before it, the Court accepted that the perforation was a recognised surgical complication, capable of occurring even when a procedure is performed with reasonable skill and care.
The Court’s reasoning is firmly grounded in established authority. In cases such as Van Wyk v Lewis, Hucks v Cole, and Castell v De Greef, courts have consistently acknowledged that medical treatment, particularly surgery, is not an exact science. Even with competence and diligence, adverse outcomes sometimes occur.
This judicial caution exists for good reason. To succeed in a medical negligence claim, a plaintiff must establish not only that the practitioner caused the harm, but that the practitioner’s conduct was negligent when measured against the standard of a reasonably competent professional in the same field. What may appear obvious to a lay observer may, on proper clinical analysis, be an inherent risk or unavoidable complication.
Medical science is complex, outcomes are uncertain, and perfection is not the legal benchmark. Courts therefore refuse to substitute assumption for proof or hindsight for evidence.
As Kotzé JA observed in Van Wyk v Lewis, where the evidence at the conclusion of a case is evenly balanced, the plaintiff cannot succeed, having failed to discharge the onus of proof. The principle remains settled. Suspicion is not enough. Proof is required.
