On May 28, 2025, Louisiana Governor Jeff Landry signed House Bill 450 (HB 450) into law as Act No. 18, which will majorly shift how medical causation is proven in personal injury lawsuits filed in Louisiana. The new law enacts Louisiana Code of Evidence Article 306.1 and explicitly overrides a legal presumption that has been relied on by plaintiffs and recognized by courts for over three decades. Insurance defense counsel can now challenge causation more aggressively without needing to overcome an implied presumption.

The law’s effect will have a significant effect on personal injury claims brought in Louisiana state courts: In personal injury cases governed by tort law — excluding those filed under the Louisiana Workers’ Compensation Law — Plaintiffs can no longer rely on a lack of prior illness or injury to create a presumption that their current medical condition was caused by the event at issue in the lawsuit. This change raises the evidentiary burden and will likely reshape how injury cases are litigated in Louisiana moving forward.

What Did the Law Change?

Prior to the enactment of Act No. 18, Louisiana courts applied what became known as the Housley presumption, named after the 1991 Louisiana Supreme Court case Housley v. Cerise, 579 So. 2d 973. In Housley, the Court held that when a plaintiff was in good health before an accident, and disabling symptoms appeared immediately after and persisted, the trial court could presume that the accident caused the injury — as long as there was some reasonable medical evidence supporting such a causal link.

Once the Housley presumption applied, the burden shifted to the defendant to rebut the presumption, requiring the defense to present medical testimony or evidence of an alternative cause.

Article 306.1 now eliminates this presumption for any personal injury claim filed on or after the law’s effective date. It states:

“Notwithstanding any other provision of law, in a claim for personal injury damages that is not raised pursuant to the Louisiana Workers’ Compensation Law, the lack of a prior history of an illness, injury, or condition shall not create a presumption that an illness, injury, or condition was caused by the act that is the subject of the claim.”

Importantly, the statute does not bar plaintiffs from introducing medical records or testimony about their prior health. What it eliminates is the ability to presume causation based solely on the fact that the plaintiff was healthy before, and symptomatic after, an accident.

Why This Matters

This significant change establishes that the timing of symptoms following an accident is not enough to establish medical causation of injuries. Plaintiffs will need to provide affirmative, medically supported evidence that directly ties the claimed condition to the specific event in question.

On the defense side, defense counsel can now challenge causation more aggressively without needing to overcome an implied presumption. Medical records, prior treatment histories, and expert evaluations will play a key role in evaluating claims and crafting early litigation strategy.

Limits

Article 306.1 does not apply retroactively. The statute expressly states it is to be applied prospectively only, meaning it affects only causes of action arising on or after the date Governor Landry signed the bill. Any pending case filed based on an accident or injury that occurred before May 28, 2025, may still rely on the Housley presumption if the requisite elements are met.

The law also does not affect claims made under the Louisiana Workers’ Compensation Law, which continues to operate under its own evidentiary rules. Nor does it prohibit plaintiffs from presenting evidence of good prior health — It simply removes the presumption courts used to draw from that fact alone.

Conclusion

Following the passage of HB 450, Plaintiffs can no longer rely on the absence of prior injuries to support causation, which will emphasize the importance of obtaining and maintaining complete medical records for their injury claim. Defendants can challenge causation more easily, forcing plaintiffs to establish a direct and medically supported link between the incident and the claimed injury. Effective immediately and only to prospective claims, the new Code of Evidence Article 306.1 represents a significant change to the evidentiary framework in Louisiana personal injury litigation.

Louisiana Tort Reform Legislation

Read all articles on Louisiana’s new tort reform legislation:

Louisiana HB 436: What Immigration Status Means in an Automobile Accident

Louisiana HB 148: Increased Insurance Regulations and Increased Consumer Participation

HB 431: A Major Change to Civil Liability in Louisiana

HB 434: How the No Pay, No Play Rule is Changing in Louisiana

HB 450 Ends Longstanding Presumption of Causation in Louisiana Personal Injury Cases

Louisiana HB 549 – Dashcams for Discount