The Tylenol autism litigation involves product liability claims alleging that prenatal acetaminophen exposure may contribute to autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and related neurodevelopmental disorders.
The federal Tylenol lawsuits were consolidated in the Southern District of New York after plaintiffs filed claims against the manufacturer of Tylenol and retailers that sold store-brand acetaminophen products.
Tylenol autism ADHD lawsuits generally allege that defendants failed to adequately warn pregnant consumers about a possible association between acetaminophen use and later neurodevelopmental diagnoses in their children.
The federal litigation has focused heavily on whether plaintiffs can present admissible expert testimony and scientific evidence linking acetaminophen to ASD and ADHD.
Judge Cote excluded the plaintiffs’ initial general-causation experts in 2023, a ruling that ultimately resulted in judgments against plaintiffs in approximately 550 cases.
In July 2026, the Second Circuit vacated those judgments after finding errors in the district court’s evaluation of several experts, but the appellate court did not decide that prenatal acetaminophen exposure causes ASD or ADHD.
Tylenol autism and ADHD lawsuits are generally based on allegations that:
- Acetaminophen manufacturers and retailers knew or should have known about research examining an association between prenatal acetaminophen exposure and ASD or ADHD.
- Product labels allegedly failed to provide adequate warnings about potential neurodevelopmental risks associated with acetaminophen use during pregnancy.
- Pregnant consumers allegedly used Tylenol or store-brand acetaminophen without receiving sufficient information about the potential risks identified in published research.
- Prenatal acetaminophen exposure allegedly contributed to a child later developing ASD, ADHD, or both.
- Manufacturers and retailers may be liable under applicable state product liability and failure-to-warn laws if plaintiffs can prove causation and the remaining elements of their individual claims.
A 2020 JAMA Pediatrics study found that acetaminophen detected in newborn meconium was associated with increased odds of an ADHD diagnosis, and the researchers noted that earlier cohort studies had produced a pooled relative risk of 1.34 for ADHD following prenatal exposure.
The FDA initiated a process in 2025 to revise acetaminophen labeling to address evidence of a possible association with autism and ADHD, while the Society for Maternal-Fetal Medicine, in guidance endorsed by the American College of Obstetricians and Gynecologists, continues to recommend acetaminophen as a first-line treatment for pain and fever during pregnancy and states that current evidence does not establish causation.
On remand, plaintiffs must still establish causation and the other elements of their state-law claims, as the Second Circuit’s decision addressed the treatment of expert evidence rather than whether acetaminophen causes ASD or ADHD.
Is There a Tylenol Class Action Lawsuit?
There is no certified Tylenol class action lawsuit for autism or ADHD claims.
Instead, many Tylenol lawsuits filed in federal court have been coordinated through multidistrict litigation, or MDL, in the Southern District of New York.
The Tylenol MDL allows cases involving similar allegations and scientific issues to proceed together for pretrial matters while each plaintiff keeps an individual claim.
Unlike a class action, an MDL does not combine every plaintiff into a single case with one shared outcome.
Plaintiffs may still need to prove individual facts such as prenatal acetaminophen exposure, diagnosis, causation, and damages.
Separate acetaminophen lawsuits may also proceed in state courts outside the federal MDL.
