Published July 23, 2026
The federal Tylenol autism and ADHD litigation, which had largely collapsed after a sweeping dismissal in late 2024, is back in play. On July 13, 2026, a three-judge panel of the U.S. Court of Appeals for the Second Circuit reversed a lower court's decision to exclude key expert testimony, reviving more than 500 lawsuits that allege prenatal use of acetaminophen (the active ingredient in Tylenol) contributed to a child's autism spectrum disorder or ADHD.
The reversal centers on three of the plaintiffs' expert witnesses, including researchers from Harvard, Columbia, and Albert Einstein College of Medicine, whose opinions the appeals panel found should not have been kept from a jury. The panel was careful to note that its ruling is limited to whether that expert evidence is admissible — it does not decide whether acetaminophen actually causes autism or ADHD, and it does not require any change to Tylenol's label or marketing.
With the expert testimony reinstated, the cases return to U.S. District Judge Denise Cote in the Southern District of New York, where the litigation had been centralized. From here, the more than 500 revived cases are positioned to move toward renewed pretrial proceedings and, potentially, bellwether trials — a small set of representative cases tried first to help both sides gauge how a jury might respond to the evidence before larger settlement talks take shape.
Kenvue, the Johnson & Johnson spinoff that owns Tylenol, said it plans to challenge the reliability of the experts' opinions again and continues to maintain that no causal link between acetaminophen and autism or ADHD has been established. The company's stock fell on the news, reflecting investor concern that the litigation — which many had assumed was effectively over — has new life.
For families who already filed a federal claim, this reversal reopens a path to trial or settlement that looked closed just months ago. For families who haven't filed yet, it's a reminder that this litigation is active and evolving quickly, and that state-level filing deadlines don't pause while the federal case works through appeals. See Atumio's Tylenol autism lawsuit page for a free eligibility review, or start your case review directly.