Tylenol Maker Fights Ruling That Revived 500 Autism Lawsuits
Tylenol maker Kenvue and several major retailers are asking a federal appeals court to reconsider a decision that revived more than 500 lawsuits alleging that acetaminophen use during pregnancy contributed to autism or ADHD in children.
In a filing Thursday, Kenvue and defendants including Walmart, CVS, Walgreens and Target urged the 2nd U.S. Circuit Court of Appeals to revisit its July 13 ruling reopening the litigation. The companies argue that the court gave too little weight to U.S. District Judge Denise Cote’s decision to exclude key expert testimony offered by families bringing the cases.
Cote had found that the plaintiffs lacked reliable expert evidence to establish that prenatal acetaminophen exposure can cause autism spectrum disorder or attention-deficit/hyperactivity disorder. Her ruling led to the dismissal of more than 500 claims.
The Second Circuit revived much of the litigation in July after finding that Cote applied the federal standard for expert testimony too strictly to three of the plaintiffs’ witnesses. The panel said their methods were used by other scientists and that disputes over their conclusions could be tested as the cases moved forward.
Kenvue and the retailers now say the ruling weakened a trial judge’s role in screening scientific evidence before it reaches a jury. Their filing asks the court to restore Cote’s decision and again exclude the testimony.
The fight over those experts could determine whether hundreds of claims survive. The families rely on expert evidence to establish general causation, meaning whether prenatal exposure to acetaminophen is capable of causing the conditions alleged in the lawsuits. Without admissible evidence on that question, their individual claims face a major hurdle.
Federal Rule of Evidence 702 requires judges to assess the reliability of expert testimony before jurors can consider it. Kenvue argues that Cote performed that role correctly when she examined the studies and reasoning underlying the plaintiffs’ opinions.
The July ruling involved testimony from Harvard T.H. Chan School of Public Health dean Andrea Baccarelli, Albert Einstein College of Medicine professor Eric Hollander and toxicologist Brandon Pearson, formerly of Columbia University.
The appeals court concluded that Cote had crossed from evaluating the reliability of their methods into weighing competing interpretations of scientific research. Questions over which interpretation is more persuasive can be addressed through opposing experts, cross-examination and ultimately a jury, the panel found.
Kenvue and the retailers dispute that approach. They argue that weaknesses in the experts’ reasoning should have kept the testimony out of court rather than become issues for jurors to sort through at trial.
The companies also asked the Second Circuit for a narrower ruling that would give Cote another opportunity to examine the three experts under Rule 702 as the cases return to her court. That could leave another significant fight over expert testimony ahead even if the July decision remains in place.
The appeals court’s ruling focused on whether the plaintiffs could use the disputed expert opinions. The broader scientific question of whether acetaminophen use during pregnancy causes autism or ADHD remains unresolved.
Parents and guardians bringing the cases accuse Kenvue and retailers of failing to warn consumers about risks they say were associated with taking acetaminophen during pregnancy. Kenvue disputes the allegations and maintains that Tylenol is safe when used as directed.
Kenvue was spun off from Johnson & Johnson in 2023 and now owns the Tylenol brand.
The Second Circuit rarely grants requests to reconsider its own decisions. Its response to the new filing will determine whether the July ruling stands as written or whether the court reopens the expert evidence dispute that brought hundreds of Tylenol lawsuits back into play.
