Appeals court revives more than 500 Tylenol autism lawsuits

The 2nd U.S. Circuit Court of Appeals in Manhattan revived more than 500 private lawsuits over Tylenol and alleged links to autism and ADHD. The court ruled that the lower court improperly excluded testimony from expert witnesses offered by parents and guardians, reopening claims against Kenvue and keeping pharmacies and retailers, including Walgreen Co., in the case.

The litigation sits inside In re Acetaminophen - ASD-ADHD Products Liability Litigation, a multidistrict proceeding in the Southern District of New York that began in 2022. The plaintiffs, a mix of children, parents and guardians, allege that prenatal exposure to acetaminophen caused autism spectrum disorder and/or attention deficit/hyperactivity disorder. U.S. District Judge Denise Cote had dismissed the lawsuits after finding the plaintiffs’ scientific experts had not provided credible evidence tying Tylenol, or its active ingredient acetaminophen, to autism or ADHD.

The appellate ruling was issued on July 13, 2026, after argument on November 17, 2025. The lawsuits can move forward again, and the expert evidence Judge Cote rejected will get another look under the appeals court’s reasoning.

In September 2025, the U.S. Food and Drug Administration initiated the process for a label change for acetaminophen and warned that use during pregnancy may be associated with an increased risk of neurological conditions such as autism and ADHD in children. The agency also told physicians to consider minimizing use for routine low-grade fevers. The American College of Obstetricians and Gynecologists called acetaminophen well studied and safe in pregnancy when used as directed. Kenvue, which makes Tylenol, has repeatedly reviewed the science and found no causal association.