Tylenol is displayed for sale at a CVS Pharmacy on Nov. 3, 2025 in Austin, Texas.
Brandon Bell | Getty Images
A federal appeals court on Monday revived more than 500 private lawsuits against Tylenol maker Kenvue over the painkiller’s alleged link to autism.
The 2nd U.S. Circuit Court of Appeals in Manhattan said a district court judge improperly excluded expert testimony from three doctors offered by parents and guardians who tied Tylenol use during pregnancy to autism and attention deficit hyperactivity disorder (ADHD) in children.
There is no firm scientific evidence of such a link. The issue drew greater attention after President Donald Trump and top U.S. health officials in September suggested a link to autism.
In a 64-page decision for a three-judge panel, Circuit Judge Guido Calabresi said the testimony from the three doctors reflected methodologies used by other scientists, and “constitute acceptable interpretations of scientific evidence where scientists may, and in fact do, disagree.”
Kenvue agreed to be acquired by Kleenex tissue maker Kimberly-Clark for more than $40 billion last November.
In a statement to CNBC, Kenvue said, “We stand behind the safety of our product and will continue to defend these cases.”
Many retailers and pharmacy operators including CVS, Kroger, Target, Walgreens and Walmart were also named as defendants.
Shares of Kenvue traded down 20 cents at $19.28 in morning trading.
Doctors and medical societies consider acetaminophen, the active ingredient in Tylenol, the preferred means to treat pain and fever during pregnancy, and Kenvue has long maintained that Tylenol is safe.
Kenvue’s former parent Johnson & Johnson made Tylenol for more than 60 years, and has also defended its safety.
Harvard dean’s testimony allowed
Calabresi stressed that the appeals court was not deciding whether using acetaminophen causes autism or ADHD, or whether elected officials should do more to protect public health.
He said the doctors whose testimony was wrongly excluded included Andrea Baccarelli, the dean of Harvard University’s School of Public Health; Eric Hollander, a psychiatry professor at the Albert Einstein College of Medicine, and Brandon Pearson, a toxicologist at Columbia University.
“We are pleased that the panel unanimously found that our key experts reliably applied their scientific methods and principles,” Ashley Keller, a lawyer for the parents, said in an email.
Kenvue, based in Summit, New Jersey, was spun off in 2023 by Johnson & Johnson.
The private lawsuits were dismissed in December 2024 by U.S. District Judge Denise Cote in Manhattan, who criticized the methodology of the plaintiffs’ expert witnesses.
Experts often play a key role in product liability lawsuits such as the Tylenol cases.
Monday’s decision returns the lawsuits to Cote for further proceedings.
— CNBC contributed reporting.