At Belzuz Abogados S.L.P., our Insurance Law Department has handled numerous medical liability cases in which this doctrine has been invoked. It operates as an exception to the general rule set out in Article 217 of the Spanish Civil Procedure Act, which places on the claimant the burden of proving fault, actual damage, and the causal link between the conduct and the harm suffered.
- General Principle and Rationale for the Exception
As a rule, any person alleging harm and seeking judicial protection must prove:
- The existence of negligent or wrongful conduct,
- Actual and demonstrable harm,
- A causal link between the conduct and the damage suffered.
However, in the medical field there are situations in which the harm is so markedly disproportionate to the medical act performed that the outcome appears, from the patient’s perspective, objectively inexplicable. A paradigmatic example would be a minor procedure—such as the removal of a wart—resulting in a serious deterioration of the patient’s health.
In such cases, the injury is clearly inconsistent with the foreseeable risks of the procedure, making it reasonable to require the professional to explain what occurred. This shift in the burden of proof is grounded in the principle of availability and ease of proof, as reflected in Article 217.7 LEC, which obliges courts to consider which party is better positioned to provide certain evidence.
- Jurisprudential Foundations
The Supreme Court has outlined the contours of this doctrine. According to Judgment 828/2021, 30 November (rec. 5955/2018), disproportionate damage does not automatically entail a reversal of the burden of proof. Rather, it requires the professional to offer a reasonable and coherent explanation of the discrepancy between the low risk inherent in the medical act and the severity of the outcome. Where no such explanation is provided, negligence may be inferred.
Similarly, Judgment 635/2018, 16 November (rec. 1250/2016) indicates that in cases where the harm typically occurs only in the presence of negligent conduct, the doctrine permits a presumption of fault when the professional fails to adequately justify the result.
The Supreme Court also warns against its mechanical or automatic application. Judgment 698/2016, 24 November (rec. 455/2014) stresses that disproportionate damage is not an autonomous presumption of negligence, but rather a tool of evidentiary assessment when the result is ordinarily linked to negligent conduct and the professional does not provide a consistent explanation.
Moreover, the doctrine does not apply where a medical cause legitimately justifies the harmful outcome. Judgment 240/2016, 12 April (rec. 618/2014) affirms that if the harm stems from a factor unrelated to the professional’s conduct—such as complications associated with a pre-existing condition—the doctrine cannot be invoked.
In the same line, Judgment 288/2014, 29 May (rec. 888/2012) states that when there is a plausible medical explanation for the harm, the case cannot be assessed under this doctrine, and liability must instead be examined based on an identifiable breach of the lex artis, such as the incorrect placement of an endotracheal tube, rather than the mere occurrence of a severe outcome.
- Conditions for Application
The doctrine of disproportionate damage may be applied when:
- The harm is extraordinarily serious in relation to the procedure performed,
- There is no reasonable medical explanation for such harm,
- The professional holds the factual information necessary to clarify what occurred,
- The absence of an adequate explanation reasonably allows an inference of negligent conduct.
Conversely, the doctrine does not apply when:
- The harm corresponds to a known or inherent complication of the procedure, or
- There exists a medically established cause independent of the professional’s actions.
- Conclusion
The doctrine of disproportionate damage is an important evidentiary mechanism designed to protect patients faced with highly unusual and severe outcomes that—unless properly explained—reasonably suggest negligence. It does not automatically reverse the burden of proof, but it does require the professional—who possesses the relevant information—to provide a convincing explanation. If no such explanation is offered, courts may conclude that negligence occurred.
The Insurance Law Department at Belzuz Abogados S.L.P. remains at your disposal to assess any case involving civil or insurance liability with the highest level of legal rigor and professionalism.