Product Liability
Acetaminophen and Autism Claims: What MDL 3043 Shows
A factual review of the acetaminophen and autism litigation: MDL 3043 in New York, the court's rulings on expert testimony, and what remains undecided.
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Acetaminophen is the active ingredient in Tylenol and in many other pain, fever and cold products sold in the United States. Since 2022, federal lawsuits have alleged that use of acetaminophen during pregnancy caused children to develop autism spectrum disorder (ASD) or attention deficit/hyperactivity disorder (ADHD). The cases are consolidated in the Southern District of New York as MDL No. 3043, before Judge Denise L. Cote. The Judicial Panel on Multidistrict Litigation’s October 1, 2026 statistics report lists 113 actions pending, out of 777 filed in total. The court has dismissed parts of the claims and has excluded the plaintiffs’ causation experts, and no court has found that acetaminophen caused any child’s condition.
The claims and the court hearing them
The court’s own page for the proceeding, In re Acetaminophen - ASD-ADHD Products Liability Litigation, states the plaintiffs’ theory in the court’s words: “The plaintiffs in this multidistrict litigation (“MDL”) assert that children developed autism spectrum disorder and/or attention deficit/hyperactivity disorder as a result of in utero exposure to acetaminophen.” That sentence describes the plaintiffs’ allegation. It is not a finding by the court.
The same page gives the docket numbers: 1:22-md-3043 (DLC) for the MDL docket and 1:22-mc-3043 (DLC) for the master case file. The proceeding is assigned to Judge Denise L. Cote, with Magistrate Judge Katharine H. Parker, and its nature-of-suit code is 367, personal injury arising from a pharmaceutical product.
What is established vs. what is alleged
Established by the documents cited here: the MDL exists and is active, with 113 actions pending as of the Panel’s October 1, 2026 report; the court has issued the orders listed on its MDL page, including rulings on motions to dismiss and on the admissibility of expert testimony; and consolidation is for pretrial proceedings only, with each plaintiff keeping an individual claim.
Alleged, and not decided: that exposure to acetaminophen in the womb causes autism or ADHD in any child, and that the manufacturers failed to warn of that risk. The court’s page records that assertion as the plaintiffs’ claim. No order reviewed here finds that acetaminophen caused any child’s condition.
The court’s rulings on the causation experts
The most consequential orders in the public record concern the scientific testimony the plaintiffs offered to prove that acetaminophen causes autism or ADHD.
On December 18, 2023, the court ruled on the parties’ Rule 702 motions in an opinion docketed at ECF 1381. The opinion excluded the testimony of the five experts the plaintiffs had relied on for general causation. The court observed that none of the plaintiffs’ experts had published research expressing the ultimate opinions they offered, and that the plaintiffs’ lead causation expert had co-authored a 2022 study on the prenatal effects of acetaminophen that cautioned against any change in clinical practice.
After that ruling, according to a second opinion dated July 10, 2024 and docketed at ECF 1494, plaintiffs in more recently filed actions relied on another expert, Dr. Roberta Ness, who opined that prenatal exposure to acetaminophen causes ADHD. The court granted the defendants’ motion to preclude her testimony. It found her causation analysis “not an objective or rigorous application of scientific methodology,” described it as “result driven,” and pointed to her treatment of confounding by genetics.
Earlier, on November 14, 2022, the court denied motions to dismiss on the ground of preemption in two of the individual actions. A series of opinions in April and May 2023 then resolved renewed motions to dismiss. The court denied dismissal on preemption and Rule 8 grounds, granted dismissal of a consumer protection claim on express preemption, granted in part and denied in part dismissal of misrepresentation claims, granted dismissal of a standalone apparent manufacturer claim, and granted in part and denied in part dismissal on state safe harbor laws.
Where the claims stand procedurally
MDL No. 3043 is a consolidated pretrial proceeding, not a class action. The Panel created no class and certified none; each plaintiff keeps an individual claim, and the guide to MDLs and class actions explains why the two mechanisms resolve different parts of a mass injury. The overview of how mass tort litigation works describes how claims of this shape are organized.
The Panel’s report dated October 1, 2026 lists MDL 3043 in the Southern District of New York before Senior District Judge Denise L. Cote, with 113 actions now pending. No trial date appears in the documents reviewed here, and no settlement is recorded on the court’s MDL page or in the opinions cited.
Key dates
- November 14, 2022: the court denies motions to dismiss on the ground of preemption.
- December 1, 2022: order on defense leadership.
- December 2, 2022: orders on plaintiffs’ leadership, direct filing and short form complaints.
- January 9, 2023: orders on the common benefit fund and on discovery coordination.
- February 1, 2023: order on general causation discovery and motions.
- April 20, 2023: the court denies a motion to dismiss on the ground of preemption.
- April 21, 2023: the court grants dismissal of a consumer protection claim on express preemption.
- April 27, 2023: the court denies dismissal on Rule 8 grounds and grants in part and denies in part dismissal of misrepresentation claims.
- April 28, 2023: the court grants dismissal of a standalone apparent manufacturer claim and denies dismissal on the ground of an innocent seller provision.
- May 15, 2023: the court grants in part and denies in part dismissal on the ground of state safe harbor laws.
- July 31, 2023: order on amended short form complaints and renewed motions to dismiss.
- August 3, 2023: the court denies a motion to certify two opinions for interlocutory appeal.
- December 18, 2023: the court grants the motion to exclude the plaintiffs’ expert opinions.
- July 10, 2024: the court grants a second motion to exclude the plaintiffs’ expert opinions.
- October 1, 2026: the Judicial Panel on Multidistrict Litigation reports 113 actions pending in MDL 3043.
What this does not establish
Excluding an expert witness is a ruling on whether testimony may be presented. It is not a finding that acetaminophen does or does not cause autism or ADHD, and the court did not decide the underlying scientific question in the orders reviewed here.
No order reviewed here awards damages, approves a settlement, or finds any defendant liable. The pending-case count measures how many actions are before the court, not how strong those actions are.
This article reports what the litigation record shows. It is not medical advice and it does not address whether any particular person should use acetaminophen.
Frequently asked questions
What is MDL 3043?
MDL No. 3043 is the federal multidistrict proceeding, In re Acetaminophen - ASD-ADHD Products Liability Litigation, used to coordinate pretrial proceedings in lawsuits alleging that prenatal exposure to acetaminophen caused autism spectrum disorder or ADHD. It sits in the Southern District of New York before Judge Denise L. Cote, on the docket 1:22-md-3043 (DLC).
Has a court found that acetaminophen causes autism?
No. The orders cited here do not find that acetaminophen caused any child’s condition. The court excluded the plaintiffs’ five causation experts in December 2023 and excluded a later expert in July 2024. Rulings on expert testimony decide whether evidence may be presented, not whether a product caused an injury.
Are these lawsuits still active?
Yes. The Panel’s October 1, 2026 statistics report lists 113 actions pending in MDL 3043, out of 777 filed in total.
Does this article say whether acetaminophen is safe to use?
No. This article reports what the litigation record shows. Questions about using any medicine during pregnancy are medical questions for a clinician, and nothing here should be read as guidance either way.
Sources
- U.S. Judicial Panel on Multidistrict Litigation: “MDL Statistics Report: Distribution of Pending MDL Dockets by District, Report Date 10/1/2026” (link, accessed 2026-10-13)
- U.S. District Court for the Southern District of New York: “In re Acetaminophen - ASD-ADHD Products Liability Litigation (MDL 3043)” (link, accessed 2026-10-13)
- U.S. District Court for the Southern District of New York: “Opinion and Order on Rule 702 motions, In re Acetaminophen - ASD-ADHD Products Liability Litigation, No. 22md3043 (DLC), ECF 1381 (December 18, 2023)” (link, accessed 2026-10-13)
- U.S. District Court for the Southern District of New York: “Opinion and Order granting the motion to preclude the testimony of Dr. Roberta Ness, No. 22md3043 (DLC), ECF 1494 (July 10, 2024)” (link, accessed 2026-10-13)
- U.S. District Court for the Southern District of New York: “Opinion and Order denying motions to dismiss on the ground of preemption, No. 22md3043 (DLC) (November 14, 2022)” (link, accessed 2026-10-13)
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