Appeals Court Revives Tylenol Lawsuits Over Autism Claims

A federal appeals court in New York revived lawsuits that allege acetaminophen, the active ingredient in Tylenol, caused autism in children when used by pregnant mothers. The Second U.S. Circuit Court of Appeals found that a trial judge had wrongly excluded expert testimony in dismissing the litigation. This decision on May 23, 2024, allows plaintiffs to proceed with their claims, which had been previously dismissed by U.S. District Judge Dora Irizarry in Brooklyn.

The lawsuits consolidate claims from hundreds of families across the United States. These families contend that their children developed autism spectrum disorder due to their mothers' prenatal exposure to acetaminophen. The core of the plaintiffs' argument rests on scientific studies suggesting a potential link between acetaminophen use during pregnancy and an increased risk of autism or attention-deficit/hyperactivity disorder (ADHD) in children. However, the scientific consensus on this link remains a subject of ongoing debate and research.

In the initial dismissals, Judge Irizarry ruled that the plaintiffs' experts had not provided sufficient evidence to establish a causal link between acetaminophen and autism. She cited a lack of reliable scientific methodology in the experts' analyses. The appeals court, however, disagreed with this assessment, stating that the trial judge applied too strict a standard for admitting expert testimony. The panel indicated that the excluded testimony, which included epidemiological studies and biological plausibility arguments, should have been considered.

This ruling does not definitively establish a causal link between Tylenol and autism. Instead, it permits the lawsuits to move forward, potentially leading to further legal proceedings and expert testimony. The defendants, including Johnson & Johnson, have consistently denied that their products cause autism, pointing to numerous studies that have not found a conclusive link. The case will now return to the lower court for further proceedings, where the admissibility and weight of the expert evidence will be re-examined.