A federal appeals court in Manhattan has breathed new life into more than 500 private lawsuits claiming that prenatal exposure to Tylenol’s active ingredient, acetaminophen, contributed to autism or attention‑deficit/hyperactivity disorder in children. The decision sends the consolidated litigation back to the same trial judge who previously tossed the cases, and zeroes in on whether plaintiffs’ scientific experts were wrongly shown the door rather than on the core question of whether the drug actually causes these conditions.
Writing for a three‑judge panel in a 64‑page opinion, Circuit Judge Guido Calabresi said the plaintiffs’ experts were using methods that “constitute acceptable interpretations of scientific evidence where scientists may, and in fact do, disagree,” emphasizing that such disputes are usually for juries to sort out, according to Reuters. The court did not decide whether acetaminophen actually causes any neurodevelopmental disorder.
Kenvue, the company behind Tylenol, responded that it “stands behind the safety of our product” and will “continue to defend these cases,” reiterating that leading medical organizations recommend acetaminophen for fever and pain in pregnancy when it is used as directed. Kenvue also noted that it was spun off from Johnson & Johnson and is headquartered in Summit, New Jersey.
Who the Court Said Should Testify
The appeals panel concluded that the lower court went too far in shutting out testimony from three key experts whose approaches, the judges said, fall within the range of methods accepted by other scientists. Those experts are Andrea Baccarelli of the Harvard T.H. Chan School of Public Health, Eric Hollander of Albert Einstein College of Medicine, and Brandon Pearson of Columbia University. Plaintiffs’ lawyer Ashley Keller said she was “pleased” that the panel found the experts had reliably applied scientific methods, per Reuters.
What Medical Groups and Researchers Say
Major medical organizations are urging the public not to read more into the ruling than what it actually covers. The American College of Obstetricians and Gynecologists has reaffirmed that current evidence is not conclusive and that acetaminophen remains an appropriate option for fever and pain in pregnancy when it is medically indicated. The American Academy of Pediatrics likewise says no causal link has been established. ACOG, the AAP, and other professional societies continue to stress short, clinically guided use.
At the same time, a 2025 systematic review that included Harvard researchers reported an association between prenatal acetaminophen use and later diagnoses of autism or ADHD, which its authors said warrants more study rather than immediate changes in medical practice. That work and its context are detailed by Harvard Chan.
What Happens Next
The appeals court sent the consolidated federal cases back to U.S. District Judge Denise Cote in Manhattan, which means the multidistrict litigation will reopen for more fights over expert admissibility, additional discovery, and potentially a round of bellwether trials, according to Bloomberg Law. Whatever happens in Manhattan is only part of the story, though.
State‑level battles are still going. The Texas Attorney General’s consumer‑protection case is moving ahead in Panola County, as described in the AG’s court filing. See the Texas Attorney General filing and Hoodline’s earlier coverage on the AG’s bid to block Kenvue's dividend for more local detail.
Legal Implications
The ruling centers on Daubert-style gatekeeping, focusing on whether the experts’ methods are sound enough to be heard by a jury, not whether their ultimate conclusions are correct. That approach could tilt the playing field in product‑liability mass torts if more expert testimony reaches jurors instead of being cut off at the courthouse door. Legal analysts note that sending the case back to the trial court does not establish causation, but it does give plaintiffs another shot at presenting their evidence to a jury. For a deeper dive into what this might mean for Kenvue and similar cases, see analysis at LegalClarity.
