The news: A federal appeals court revived more than 500 lawsuits against Tylenol maker Kenvue over acetaminophen’s alleged link to autism and ADHD, reversing a December 2024 dismissal. The panel ruled that a lower court judge improperly excluded 2024 expert testimony from three doctors, including Harvard T.H. Chan School of Public Health dean Andrea Baccarelli, whose report concluded that available evidence supported a causal association between prenatal acetaminophen exposure and neurodevelopmental disorders in children.

Why it matters: The ruling lands in the middle of a controversy that began last September, when President Trump and HHS Secretary Robert F. Kennedy Jr. warned pregnant women against taking Tylenol due to concerns over autism, despite most health experts saying their claims lacked supporting evidence. Doctors still consider acetaminophen the preferred option for pain and fever during pregnancy since alternatives like ibuprofen carry known birth-defect risks.

This week’s ruling is not about whether acetaminophen causes autism or ADHD, only that the excluded testimony reflected legitimate scientific disagreement. The decision sends the cases back to court, adding to Kenvue's legal burden as it also contends with the federal government and other regulators questioning Tylenol's safety and alleging deceptive marketing. Kenvue said it will continue defending the drug's safety profile.

The revived lawsuits also name major retailers, including CVS, Walgreens, Walmart, and Kroger, as defendants, alleging they sold private-label acetaminophen products without adequately warning that prenatal exposure could increase the risk of autism and ADHD in children. These companies may face greater pressure to review product labels and strengthen warnings.

Implications for consumer health brands and retailers: The ruling extends a legal and reputational fight Kenvue can no longer treat as resolved.

For now, consumers still trust the Tylenol brand more than any other medicine brand in the US, per Morning Consult. But renewed high-profile lawsuits could erode some of that confidence, especially among pregnant women. After the Trump administration's September press conference on Tylenol, only 32% of parents in a KFF survey said claims linking prenatal Tylenol use to autism were "definitely false," suggesting lingering uncertainty that these lawsuits could bring back into public view.

Both consumer health brands and retailers should prioritize physician- and pharmacist-first messaging, steer patients to medical society guidance on acetaminophen's safety, and monitor search and social sentiment to quickly address emerging confusion and preserve consumer confidence.