Second Circuit Revives Prenatal Acetaminophen Claims, Limits Expert Exclusions
Second Circuit revives state failure-to-warn claims in prenatal acetaminophen case.
Why it matters: This ruling alters how courts evaluate expert testimony under Rule 702 in product liability cases, affecting litigation strategy and risk management for BigLaw and corporate counsel.
- On July 13, 2026, the Second Circuit revived failure-to-warn claims linked to prenatal acetaminophen exposure.
- The court found the district court improperly excluded experts using accepted epidemiologic methods.
- Experts failing to apply Bradford Hill factors or relying on ipse dixit remained excluded.
- The ruling held state claims were not preempted by federal FDA pregnancy warning requirements.
On July 13, 2026, the U.S. Court of Appeals for the Second Circuit issued its decision in Rutledge v. Walgreen Co., reinstating state law failure-to-warn claims related to prenatal acetaminophen (Tylenol) exposure purportedly causing neurodevelopmental disorders like ADHD and ASD in children. The case challenged the district court's exclusion of plaintiffs' expert testimony under Federal Rule of Evidence 702, which had led to dismissal of these claims.
The appellate court ruled the lower court abused its discretion by excluding three expert witnesses who employed generally accepted epidemiologic methods to establish causation. This ruling reinforces that courts cannot exclude expert testimony merely because they disagree with the conclusions if the methods are scientifically accepted, reflecting limits on judicial gatekeeping under Rule 702. However, the court upheld the exclusion of two experts who failed to properly apply the Bradford Hill criteria, a recognized framework to infer causation, or relied on unsupported personal assertions (ipse dixit).
The Second Circuit also addressed the defense's preemption argument, determining that the state failure-to-warn claims were not barred by the FDA's general warnings for over-the-counter (OTC) pregnancy use of acetaminophen. This clarification has important implications for product liability litigation involving FDA-regulated products, preserving state-level claims where federal regulations do not expressly preempt them.
Legal professionals should note this decision's nuanced approach to expert evidence admissibility and federal preemption, signaling courts will closely scrutinize the methodological rigor experts bring to causation opinions without dismissing generally accepted scientific reasoning. This sets a significant precedent for future toxic tort and pharmaceutical product liability cases.
By the numbers:
- July 13, 2026 — date of Second Circuit ruling in Rutledge v. Walgreen Co.
- Three plaintiffs' experts allowed — using accepted epidemiologic methods.
- Two experts excluded — for failing to synthesize Bradford Hill factors or relying on ipse dixit.
Yes, but: While the ruling limits exclusion of experts using accepted methodologies, it still supports excluding those lacking rigorous application of causation criteria, ensuring some gatekeeping remains.
What's next: This decision may prompt renewed failure-to-warn litigation involving OTC drugs and shape expert witness preparation for product liability cases nationwide.