Updated October 16, 2026: The Second Circuit revived the federal acetaminophen autism and ADHD litigation in July 2026 and denied rehearing on October 16, according to Reuters. Earlier statements that the litigation had effectively ended are no longer current. The appellate rulings do not establish that acetaminophen causes autism or ADHD.
Families allege inadequate warnings about prenatal acetaminophen use
Parents and children have brought product-liability claims alleging that acetaminophen taken during pregnancy caused autism or ADHD. They contend that manufacturers and retailers should have warned consumers about the alleged risk. The defendants dispute both the scientific basis and legal merits of the claims.
Acetaminophen, sold as Tylenol and in generic products, is an over-the-counter pain reliever and fever reducer. Kenvue makes Tylenol following the separation of Johnson & Johnson’s consumer-health business.
Individual injury claims coordinated in an MDL
The federal cases were centralized on October 5, 2022, in the Southern District of New York before Judge Denise Cote. The proceeding is MDL No. 3043. Centralization coordinates pretrial proceedings; it is not class certification and does not establish liability.
The families’ claims depend on evidence about exposure, diagnosis, causation, and the applicable warning duties. Readers should not assume that every person who used acetaminophen during pregnancy and has a child with autism qualifies for compensation.
The 2023 dismissal did not end the appellate fight
Judge Cote’s December 2023 expert-evidence ruling left plaintiffs without admissible general-causation evidence and led to judgments for the defendants.
On July 13, 2026, the Second Circuit vacated the judgments after finding that three experts had been improperly excluded. It upheld the exclusion of two others. Reuters reported that the court denied panel and en banc rehearing on October 16, leaving the revival of about 500 lawsuits intact.
The decision allows further proceedings. It does not establish that Tylenol causes autism or ADHD, require compensation, or decide whether additional warnings were legally necessary. See our updated Tylenol lawsuit overview for more detail.
What the studies can and cannot establish
Some earlier studies reported associations between prenatal acetaminophen exposure and neurodevelopmental outcomes. Those findings do not, by themselves, prove causation or establish what a manufacturer knew at a particular time.
Later research, including a large 2024 Swedish sibling-comparison study, found no association after accounting for shared family factors. Our review of the science behind the claims discusses the evidence and its limitations.
Kenvue continues to contest the alleged link. Patients should discuss medication use during pregnancy with their healthcare professional rather than treating a court ruling as medical guidance.
Editorial correction: This article has been updated to distinguish coordinated individual lawsuits from a certified class action and to reflect the 2026 appellate rulings. Earlier scientific risk descriptions have also been clarified.
