US appeals court revives hundreds of private lawsuits linking Tylenol to autism

NEW YORK - A federal appeals court revived lawsuits that claim Kenvue hid alleged risks that Tylenol could cause autism in children whose mothers took the over-the-counter pain medication while pregnant, a controversy that’s roiled the medical community.

The three-judge panel in New York said on July 13 that a lower court erred in ruling that the plaintiffs had relied on flawed science to prove Tylenol posed an increased risk of developmental issues in babies.

The panel remanded the case for further proceedings, concluding that a lower court had “exceeded its discretion” by excluding the testimony of three experts.

In 2023, a Manhattan federal judge blocked 500 cases from proceeding to trial against Kenvue, a Johnson & Johnson spinoff.

Reviving the lawsuits is a blow to Kenvue, which likely will face thousands of new lawsuits that could cost the company billions of dollars to settle, Bloomberg Intelligence estimated in March.

The decision “is a vindication for the scientific evidence our clients have presented from the outset,” said Ashley Keller, a plaintiffs’ attorney in the case.

“The Court of Appeals agreed that our experts’ analyses of the voluminous research linking prenatal acetaminophen exposure to neurodevelopmental disorders is reliable. We look forward to presenting that evidence to a jury.”

Officials at Kenvue didn’t immediately return an email seeking comment. The court, which didn’t rule on the underlying merits of the claim, said that the trial judge did have the authority to block two other experts proposed by the consumers.

The Trump administration stoked the controversy in September 2025, when it linked Tylenol to autism and urged pregnant women to avoid it. President Donald Trump urged his followers: “don’t take it.”

The allegation roiled the field of maternal medicine, as the popular painkiller has long been deemed safe and was considered the preferred treatment for pain and fever in pregnant women.

Numerous research studies and a systemic review have found no evidence that the nonprescription drug caused autism, intellectual disabilities or attention-deficit/hyperactivity disorder.

Despite the political controversy surround Tylenol, Kimberly-Clark has proceeded with a US$40 billion (S$51.7 billion) acquisition of Kenvue. Around the time that deal was announced, Kimberly-Clark said it carefully considered all lawsuit risks related to the transaction. The combination is expected to be completed later this year.

In December 2023, US District Judge Denise Cote ruled experts for the plaintiffs failed to establish a link between Tylenol and autism, attention-deficit disorders or hyperactivity.

She concluded the experts used unreliable scientific methods to show the painkiller causes those conditions. Under federal law, judges act as gatekeepers to prevent cases built on so-called junk science from moving forward.

But the 2nd US Circuit Court of Appeals on July 13 said that the court “overstepped its gatekeeping function” by excluding three of the experts.

The panel wrote that the experts used standard methodologies and offered “acceptable interpretations of scientific evidence where scientists may, and in fact do, disagree on the ultimate answer to the causal question that they are assessing.” BLOOMBERG