Does Tylenol Cause Autism? Acetaminophen Linked to Autism Spectrum Disorder

Does Tylenol cause autism? Researchers have spent more than a decade studying whether prenatal exposure to acetaminophen, the active ingredient in Tylenol and hundreds of other medications, may increase a child’s risk of developing autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and other neurodevelopmental conditions.

Numerous epidemiological studies have reported associations between acetaminophen use during pregnancy and an increased risk of autism, ADHD, or related neurodevelopmental outcomes. Researchers have also studied biological mechanisms that could explain how acetaminophen may interfere with fetal brain development.

However, the scientific evidence remains disputed.

Tylenol manufacturer Kenvue and other defendants maintain that the available evidence does not establish that acetaminophen causes autism or ADHD. Medical organizations and regulators have also cautioned against concluding that the existing research proves causation.

That scientific debate eventually became the central issue in hundreds of Tylenol autism and ADHD lawsuits filed throughout the United States.

For several years, the litigation appeared to be moving toward additional discovery and potentially the selection of cases for trial. That changed dramatically when U.S. District Judge Denise Cote excluded the plaintiffs’ general causation experts and hundreds of federal lawsuits were subsequently dismissed.

On July 13, 2026, the U.S. Court of Appeals for the Second Circuit reversed a significant portion of those rulings. The unanimous three-judge panel determined that Judge Cote improperly excluded three of the plaintiffs’ most important experts and revived more than 500 Tylenol autism and ADHD lawsuits.

The appeals court did not rule that Tylenol causes autism or ADHD. Instead, it concluded that three of the plaintiffs’ experts used sufficiently reliable scientific methods to present their opinions in court, where the defendants remain free to challenge their conclusions through cross-examination and competing expert testimony.

This article examines the scientific evidence surrounding prenatal acetaminophen exposure and neurodevelopmental disorders, the criticisms of that research, and how disagreements over the science nearly ended the federal Tylenol litigation before the Second Circuit gave hundreds of families another opportunity to pursue their claims.

The Tylenol Autism Connection: Acetaminophen Exposure During Pregnancy Linked to Heightened Risk of Autism

A reported 70% of pregnant women use acetaminophen products during pregnancy for pain relief or fever reduction. Acetaminophen is an active ingredient in over 600 medications, including the following:

• Alka-Seltzer Plus
• Actifed
• Cepacol
• DayQuil
• Excedrin
• Mucinex
• NyQuil
• Robitussin
• Sudafed
• Tylenol

We now have a body of science that provides compelling evidence that this common pain reliever can pose a danger to a developing fetus. Use of the drug has commonly been associated with adverse and complex developmental disorder conditions, including increased risks of neurodevelopmental disorders such as autism spectrum disorder and ADHD.

How Much Tylenol Is Safe During Pregnancy?

Researchers have not established a specific amount of acetaminophen exposure during pregnancy that increases the risk of autism or ADHD.

Some studies have reported stronger associations with longer durations of acetaminophen use or higher levels of prenatal exposure. The 2019 Boston Birth Cohort study, for example, found that children with the highest levels of acetaminophen metabolites in umbilical cord blood were more likely to later receive an autism or ADHD diagnosis than children with the lowest levels.

However, observational studies cannot establish a specific dose at which acetaminophen becomes dangerous during pregnancy.

This is an important limitation of the available research.

Pregnant women should not stop taking acetaminophen or change how they use medications based solely on information contained in this article. Fever and untreated pain during pregnancy can also create health risks, and patients should discuss the benefits and potential risks of medication use with their doctors.

The scientific question at the center of the Tylenol autism litigation is not whether every use of acetaminophen during pregnancy causes autism or ADHD.

Instead, researchers and courts have been examining whether the available epidemiological studies, toxicology research, animal studies, biological mechanisms, and other evidence collectively support the conclusion that prenatal acetaminophen exposure can contribute to neurodevelopmental disorders in at least some children.

That question became the central issue in hundreds of Tylenol autism and ADHD lawsuits.

Scientists Ask: Does Tylenol Cause Autism? A Review of the Medical Studies Showing Tylenol Linked to Autism Spectrum Disorder and ADHD

Tylenol Autism Consensus Statement Signed by 91 Scientists and Physicians

A consensus statement issued in 2021 was essentially a call to action as researchers could no longer ignore the overwhelming scientific evidence indicating acetaminophen use during pregnancy could cause autism spectrum disorder or attention deficit hyperactivity disorder (ADHD).

The authors stated, “The combined weight of animal and human scientific evidence is strong enough for pregnant women to be cautioned by health professionals against its indiscriminate use, both as a single ingredient and in combination with other medications.” Additionally, the authors stated, “We recommend that pregnant women should be cautioned at the beginning of pregnancy to: forego APAP (acetaminophen) unless its use is medically indicated and minimize exposure by using the lowest effective dose for the shortest possible time.”

The use of acetaminophen during pregnancy is an issue that has not received proper attention despite consistent positive associations demonstrated in study after study. This may have something to do with the anti-vaccine movement and the discredited and debunked science behind the vaccine-autism link. We fear the related stigma has resulted in a lack of attention to the danger of regular acetaminophen exposure during pregnancy.

Acetaminophen has long been considered safe to use during pregnancy and is the active ingredient in hundreds of medications. In fact, acetaminophen has been shown to be effective in treating minor to moderate pain as well as low-grade fever.

However, emerging research across twenty-six epidemiological studies and numerous animal studies demonstrates what many researchers believe to be strong evidence of a causal link between in-utero acetaminophen exposure and autism spectrum disorder (ASD).

Prenatal Tylenol Use Poses a Large Risk – Can Prenatal Use of Tylenol Cause Autism?

The authors of the consensus statement on acetaminophen and autism believe that prenatal acetaminophen exposure and perinatal use or exposure can negatively impact fetal brain development. In fact, the writers state, “consistent with the epidemiological data, studies have demonstrated that the strongest effects of long-term use and exposure occur at a time equivalent to the beginning of the third trimester of pregnancy and the time around birth in humans.”

Finally, the authors state, “We as a society should be able to take protective action when scientific evidence indicates a chemical is of concern, and not wait for unequivocal proof that a chemical is causing harm to our children. Evidence of neurodevelopmental toxicity of any type — epidemiological or toxicological or mechanistic — by itself should constitute a signal sufficient to trigger prioritization and some level of action.”

Again, researchers’ main concern is the adverse impact of acetaminophen on fetal brain development. A medical body containing strong evidence, consisting of a decade’s worth of studies linking Tylenol to autism and child development, was no longer something to be ignored. Further, new scientific research discussed in this article only increases the confidence of researchers concerning the link between Tylenol and autism. The risks of acetaminophen use by pregnant women are simply too strong to ignore. Prenatal exposure to acetaminophen has been shown time after time to result in an adverse impact on brain development in fetuses and an increased risk for a child with autism.

The scientists who penned this study referenced that the use of acetaminophen may be necessary for pregnant women in specific situations. However, they cautioned that using generic acetaminophen products or Tylenol regularly as opposed to brief instances is what concerned them.

In other words, the authors stressed that obstetricians should counsel pregnant women that the use of acetaminophen products during pregnancy should be for as brief a period of time as possible at the lowest possible dosage. Obstetricians would be wise to advise their patients of the link between acetaminophen use and autism as well.

Finally, the authors cautioned that more research needs to be conducted as to what would constitute a safe dose of acetaminophen or the appropriate levels of acetaminophen exposure for a pregnant woman and her unborn child.

European Journal of Epidemiology (2021) – A Statistical Connection Between Tylenol and Autism Diagnoses

Researchers analyzed data from 73,881 children via six previous birth cohort studies. This study on prenatal and postnatal exposure to acetaminophen appeared in the European Journal of Epidemiology. The analyses of the studies demonstrated that children with prenatal exposure to Tylenol/acetaminophen had a statistically significant increase in the diagnosis of autism spectrum disorder and ADHD.

This study showed a clear link between the use of acetaminophen by pregnant women and a child’s risk for autism spectrum disorder and/or ADHD diagnosis. This is yet another study finding acetaminophen use during pregnancy is associated with Autism Spectrum Disorder, and a baby’s in-utero exposure to acetaminophen has been shown to be associated with ASD.

An important distinction to be made is the researchers did not find any association between postnatal generic acetaminophen exposure and autism or ADHD. The findings of an increased rate and risk of autism spectrum disorder and ADHD were consistent only for prenatal use of acetaminophen.

Johns Hopkins University Boston Birth Cohort (2019) – Higher Amounts of Acetaminophen in Umbilical Blood Lead to a Higher Incidence of ASD

A 2019 study published in the scientific journal JAMA Psychiatry found cord biomarkers (umbilical cord blood samples) of fetal acetaminophen exposure were associated with a significantly increased rate of autism spectrum disorder and ADHD in a “dose-response fashion.” In other words, the greater the amount of acetaminophen found within umbilical cord blood samples, the greater the incidence rate of autism spectrum disorder or ADHD diagnosis. This is known as the Johns Hopkins University Boston Birth Cohort study, and it adds greater credence to the claim that regular use of Tylenol while pregnant could present problems.

If nothing else, the Johns Hopkins University Bloomberg School of Public Health study established that in-utero exposure to acetaminophen increased a child’s risk for autism spectrum disorder and attention deficit hyperactivity disorder, as well as other neurodevelopmental disorders.

This was a twenty-year study of pregnant women and the early life factors of their children. The researchers measured biomarkers for acetaminophen levels within the umbilical cord blood samples in 996 separate births.

Babies with the highest level of acetaminophen in their umbilical cord blood samples (found in cord plasma acetaminophen metabolites) were three times more likely to be diagnosed with Autism Spectrum Disorder or ADHD later on in life as compared to infants with the lowest level of acetaminophen.

Additionally, researchers found a consistent association between acetaminophen levels found within biomarkers of cord blood samples and autism spectrum disorder and ADHD across a number of confounding factors, including preterm birth, substance abuse, smoking, maternal stressors, and maternal BMI. The dose-response findings support the working theory that Tylenol adversely impacts fetal development. In fact, we believe this is strong evidence of a causal connection with adverse neurodevelopmental outcomes. This is the first study that demonstrated a dose-dependent association between acetaminophen exposure and autism.

Acetaminophen Use in Pregnancy and Neurodevelopment (2016) – A Clear Connection Between Tylenol and Autism

In a 2016 study published in the International Journal of Epidemiology, researchers analyzed 2644 mother-child pairs. They analyzed children at ages one and five to determine whether prenatal exposure to acetaminophen led to an increased risk for autism spectrum disorder or ADHD by measuring clinical symptoms. Researchers found a clear connection and increased risk between Tylenol use during pregnancy and autism.

This study was unique in finding an association between Tylenol use and autism dependent on the frequency of exposure to acetaminophen during pregnancy. This finding was repeated with much greater clarity in the aforementioned Johns Hopkins Boston Birth Cohort study, which again showed a dose-response factor based on the overall use of acetaminophen.

Danish National Birth Cohort Study (2015) – Maternal Use of Acetaminophen Analyzed During Pregnancy as a Risk Factor for Autism Spectrum Disorder

Researchers analyzed 64,322 mother-child pairs over 12.7 years to better understand the cause of diseases in children. This study specifically analyzed acetaminophen use during pregnancy to determine whether there was an association with an increased rate of autism spectrum disorder in offspring. This assessment has been utilized in a number of other meta-analyses of existing scientific evidence.

Scientists found that in-utero exposure to acetaminophen had an adverse effect on fetal development and led to a significant increase in diagnosis for ADHD and a notable increase in autism spectrum disorder.

JAMA Psychiatry Study (2014) – Confirms Danish Study

Another research team analyzed the Danish national birth cohort study that was conducted between 1996 – 2002. Scientists again found an increase in both ADHD and hyperkinetic disorder (abnormal involuntary movements), which is a severe form of ADHD following in-utero exposure to Tylenol/acetaminophen exposure

Acetaminophen Exposure and Fetal Brain Development (Yale Study)

Early Reports About the Tylenol-Autism (and Other Neurodevelopmental Disorders) Risks

The Yale University School of Public Health also published the findings echoed by 91 scientists in the previously mentioned consensus statement. Zeyan Liew, Ph.D., M.P.H., professor at the Yale University School of Public Health, states that Yale’s lab was among the first to report detrimental effects of acetaminophen use during pregnancy and acetaminophen exposure on fetal brain development.

It is worth noting the authors of the previously referenced consensus statement relied on twenty-five years of epidemiological, animal, and in-vitro studies in arriving at their conclusions. The research team found an increased risk for neurodevelopmental disorders such as autism spectrum disorder, attention deficit hyperactivity disorder, decreased IQ, and language delays. Overall, this common pain reliever is consistently associated with disorders relating to fetal brain development.

Acetaminophen has been shown to cross the placental barrier and is theorized to cause alterations to maternal hormones and detrimentally impact fetal development.

2022 Animal Study of Tylenol Use and Fetal Brain Development

Consistent with the totality of animal studies, in Paracetamol (Acetaminophen) and its Effect on the Developing Mouse Brain, researchers found that mice exposed to relevant doses of acetaminophen (meant to mimic regular use of Tylenol as opposed to mere occasional use) displayed reduced memory and learning ability and other signs of neurodevelopmental disorders. It appeared to the scientists that Tylenol induces oxidative stress in the hippocampus, which likely plays a large role in the manifestation of neurodevelopmental issues.

The question remains: what pain relievers will pregnant women have available in the future? Among all pain relievers, and with limited medical alternatives, Tylenol has long been thought to be safe for consumption by pregnant women.

Clearly, more research must be conducted in this area for the safety of pregnant women and their children. However, maternal use of acetaminophen products poses a higher risk for neurodevelopmental disorders such as autism. The studies clearly demonstrate that children exposed to environmental conditions in-utero and during the perinatal period, along with genetic factors, pose serious risk factors for the potential to develop autism.

Does the Scientific Evidence Prove That Tylenol Causes Autism?

The scientific evidence does not establish that every child exposed to acetaminophen during pregnancy will develop autism or ADHD.

It also does not establish that acetaminophen is the sole cause of autism.

Autism spectrum disorder is a complex neurodevelopmental condition involving genetic, environmental, and other factors that researchers continue to study.

The central scientific question is whether prenatal acetaminophen exposure may be one contributing factor that increases the risk of autism, ADHD, or other neurodevelopmental conditions in susceptible children.

Numerous epidemiological studies have reported associations between prenatal acetaminophen exposure and neurodevelopmental outcomes. Researchers have also identified potential biological mechanisms that could explain how acetaminophen may interfere with fetal brain development.

Other scientists, medical organizations, regulators, Kenvue, and defendants in the Tylenol litigation dispute whether this evidence is sufficient to establish causation.

The Second Circuit’s July 13, 2026 decision did not resolve that scientific debate.

Instead, the appeals court determined that three of the plaintiffs’ experts used sufficiently reliable scientific methods to present their causation opinions in court.

The defendants will have the opportunity to challenge those opinions and present their own scientific evidence.

For families pursuing Tylenol autism or ADHD lawsuits, the ruling means that the scientific causation question may finally be tested through the adversarial process rather than ending the litigation before the plaintiffs’ experts could present their opinions to a jury.

2022 Study Links Acetaminophen to Neurodevelopmental Injury

2022 Study Evaluates Criticisms of the Acetaminophen-Autism Research

A peer-reviewed study completed in October 2022 sheds the latest light on the link between Tylenol use during pregnancy and autism, along with other neurodevelopmental injuries. The study is entitled Acetaminophen Causes Neurodevelopmental Injury in Susceptible Babies and Children: No Valid Rationale for Controversy.

This is the first study that reviews and evaluates confounding factors for autism within the context of all prior studies on this subject to date.  Further, the authors tackle the specific criticisms of this body of scientific data within the overarching existing controversy of whether in-utero exposure to acetaminophen causes autism. 

Authors Rebut Criticism of the Science of Tylenol Link to Autism

Critics of the acetaminophen autism link argue that the rapidly climbing rates of ASD in the pediatric population are attributed to improved diagnostic criteria and awareness.  However, a careful analysis of all existing data and, more specifically, disparities between rates of autism measured in multiple birth cohort studies can only be explained by the role of an environmental factor, such as a chemical.

Another common argument pushed by both critics of the science, along with the manufacturers and retailers of generic acetaminophen and Tylenol, is that correlation does not equate to causation. Of course, no scientific study is perfect. And this issue is complicated by the ethical concerns of studying pregnant women.  

Scientists cannot ethically provide medication or chemicals known to be dangerous to mothers and unborn children.  This is why researchers are so reliant on observational data and why it is so essential to look at the entire body of science, including the studies of acetaminophen on pregnant animals.  

Multiple animal studies found that in-utero exposure to acetaminophen inhibited fetal brain development.  It is also worth noting that the animals studied were not using acetaminophen to treat medical issues such as a fever. Fever during pregnancy is a confounder (or confounding variable) for the risk of autism. Lastly, every study of pregnant women or fetal exposure demonstrated positive associations between acetaminophen and autism.

Finally, the authors conclude that after reviewing a number of potential confounders (including bias of participants) and criticisms of the science, there is a valid rationale for the conclusion that in-utero exposure to acetaminophen causes neurodevelopmental injuries such as autism spectrum disorder. Additionally, the authors discuss the mechanism of injury (how acetaminophen causes neurodevelopmental injury), which includes an increase in oxidative stress.  Increased oxidative stress levels increase the risk of autism and are consistently associated with neurodevelopmental injuries in a wide array of previous studies.

Visit this page for the latest news in autism litigation and the Tylenol autism lawsuit.

How the Scientific Evidence Nearly Ended the Tylenol Autism Lawsuits

The scientific evidence discussed throughout this article eventually became the central issue in hundreds of Tylenol autism and ADHD lawsuits filed against manufacturers and retailers of acetaminophen products.

The federal lawsuits were consolidated in multidistrict litigation before U.S. District Judge Denise Cote in the Southern District of New York.

At first, the litigation appeared to be gaining momentum.

Hundreds of families filed lawsuits alleging that manufacturers and retailers failed to adequately warn pregnant women about evidence linking prenatal acetaminophen exposure to autism and ADHD. The court established a coordinated litigation process, appointed attorneys to leadership positions, addressed motions to dismiss, and moved the cases toward discovery on general causation.

General causation became the first major test for the plaintiffs.

Why General Causation Was So Important to the Tylenol Lawsuits

Before an individual plaintiff can prove that prenatal acetaminophen exposure contributed to their child developing autism or ADHD, the plaintiff must first present reliable scientific evidence showing that acetaminophen is capable of causing the condition.

This is known as general causation.

The plaintiffs offered experts from several scientific disciplines to address different parts of the causation question.

Dr. Andrea Baccarelli, an epidemiologist who later became Dean of the Harvard T.H. Chan School of Public Health, evaluated the human epidemiological research and applied the Bradford Hill criteria to determine whether the available evidence supported a causal relationship.

Dr. Eric Hollander, a psychiatrist and professor at Albert Einstein College of Medicine, evaluated autism, ADHD, and related neurodevelopmental outcomes.

Dr. Brandon Pearson, a toxicologist at Columbia University, examined animal studies and biological mechanisms that could explain how prenatal acetaminophen exposure may interfere with fetal brain development.

The plaintiffs also offered opinions from Dr. Robert Cabrera and Dr. Stan Louie.

Together, these experts were intended to provide the scientific foundation necessary for hundreds of lawsuits to proceed.

Then the litigation came to a sudden stop.

Judge Cote Excludes the Plaintiffs’ Tylenol Autism Experts

On December 18, 2023, Judge Cote excluded all five of the plaintiffs’ general causation experts.

The ruling was devastating for the plaintiffs.

Judge Cote determined that the experts had not reliably applied accepted scientific methods when concluding that prenatal acetaminophen exposure can cause autism or ADHD.

Among other issues, she criticized the experts for relying on inconsistent epidemiological studies, failing to adequately address confounding factors, combining studies involving different neurodevelopmental outcomes, and drawing causal conclusions that the authors of some underlying studies had not reached themselves.

The court was particularly critical of how Dr. Baccarelli applied the Bradford Hill criteria.

The Bradford Hill criteria are commonly used by epidemiologists to evaluate whether an observed association may reflect a causal relationship. Judge Cote concluded that Baccarelli’s analysis did not reliably account for weaknesses and inconsistencies in the available research.

Without admissible expert testimony supporting general causation, the plaintiffs could not prove that prenatal acetaminophen exposure is capable of causing autism or ADHD.

Hundreds of federal Tylenol lawsuits were subsequently dismissed.

For families who had spent years pursuing these claims, the decision was an enormous setback.

The federal litigation was effectively stopped before any jury could hear the plaintiffs’ scientific evidence.

The Plaintiffs Appeal the Dismissal of More Than 500 Tylenol Lawsuits

The plaintiffs appealed Judge Cote’s rulings to the U.S. Court of Appeals for the Second Circuit.

Their central argument was that Judge Cote went beyond the proper role of a federal judge when evaluating expert testimony.

Federal judges serve as gatekeepers.

They must determine whether an expert is qualified and whether the expert used sufficiently reliable scientific methods to present an opinion in court.

However, judges are not supposed to decide which side has the better scientific interpretation when qualified experts use accepted methodologies and reach conclusions that other scientists dispute.

Those disagreements can be addressed through cross-examination, competing expert testimony, and arguments presented to a jury.

The plaintiffs argued that Judge Cote did more than evaluate the reliability of their experts’ methods.

They contended that she separately picked apart each expert’s analysis, weighed competing scientific evidence, resolved disagreements among scientists, and ultimately decided which scientific conclusions she found more persuasive.

The Second Circuit heard oral arguments in November 2025.

During the hearing, members of the three-judge panel questioned whether some of Judge Cote’s criticisms went to the weight of the experts’ testimony rather than whether the experts should have been prohibited from testifying entirely.

The future of hundreds of Tylenol autism and ADHD lawsuits depended on the outcome of the appeal.

July 13, 2026: Second Circuit Revives More Than 500 Tylenol Autism and ADHD Lawsuits

On July 13, 2026, the Second Circuit issued a 64-page decision that gave the federal Tylenol litigation new life.

A unanimous three-judge panel ruled that Judge Cote improperly excluded Dr. Andrea Baccarelli, Dr. Eric Hollander, and Dr. Brandon Pearson.

The appeals court determined that the three experts used scientific methodologies employed by other scientists and offered acceptable interpretations of scientific evidence about which qualified scientists can reasonably disagree.

This was the central problem the Second Circuit identified with the lower court’s analysis.

Judge Cote was permitted to evaluate whether the experts reliably applied accepted scientific methods.

However, the appeals court concluded that several of her criticisms involved disagreements over how the scientific evidence should be interpreted rather than fundamental problems that required the experts to be excluded entirely.

Dr. Baccarelli’s testimony was particularly important.

He evaluated the epidemiological evidence using the Bradford Hill criteria, a recognized framework used by scientists to determine whether an observed association may be causal.

Judge Cote criticized Baccarelli for considering studies involving autism, ADHD, symptoms associated with these conditions, and other neurodevelopmental outcomes together.

The Second Circuit disagreed that this approach made his methodology unreliable.

The appeals court concluded that Baccarelli explained why he considered the broader body of neurodevelopmental research and identified scientific literature supporting his approach.

The Second Circuit also determined that the district court improperly resolved disputed questions involving potential confounding factors.

One of the major criticisms of research linking acetaminophen to autism and ADHD is confounding by genetics and by indication.

Confounding by indication refers to the possibility that the underlying reason a pregnant woman took acetaminophen, such as an infection or fever, contributed to the child’s neurodevelopmental condition rather than the medication itself.

The plaintiffs’ experts considered these issues and explained why they believed the available evidence continued to support their conclusions.

The Second Circuit determined that disagreements over how much weight to give these potential confounding factors did not justify excluding the experts entirely.

Similar issues affected Judge Cote’s evaluation of Dr. Hollander and Dr. Pearson.

The three experts approached general causation from different scientific disciplines.

Baccarelli evaluated the epidemiological evidence.

Hollander considered autism, ADHD, and related neurodevelopmental outcomes from the perspective of psychiatry.

Pearson evaluated toxicological evidence and possible biological mechanisms through which prenatal acetaminophen exposure could affect fetal brain development.

Their opinions were not identical because they were not supposed to be.

The experts addressed different pieces of the causation question.

The Second Circuit concluded that the methodologies used by these three experts were sufficiently reliable to allow them to present their opinions in court.

The Appeals Court Did Not Reinstate Every Tylenol Expert

The July 13 decision was a major victory for plaintiffs, but the Second Circuit did not reverse every ruling made by Judge Cote.

The appeals court upheld the exclusion of Dr. Robert Cabrera and Dr. Stan Louie.

The panel concluded that Dr. Cabrera did not adequately weigh and synthesize the Bradford Hill factors when reaching his causation opinion.

The court also found that Dr. Louie did not reliably explain the dosage and duration thresholds he proposed for prenatal acetaminophen exposure.

The Second Circuit also declined to decide whether Dr. Roberta Ness should be permitted to testify in a separate group of ADHD-only cases.

Because the court reinstated Baccarelli, Hollander, and Pearson, it determined that resolving the admissibility of Ness’s testimony was unnecessary at this stage of the litigation.

Does the Second Circuit Decision Mean Tylenol Causes Autism?

No.

The Second Circuit did not rule that Tylenol causes autism or ADHD.

The appeals court also did not determine that the plaintiffs’ experts are correct.

Instead, the court ruled that three experts used sufficiently reliable scientific methods to present their opinions in court.

That is an extremely important distinction.

Kenvue and the other defendants remain free to challenge the plaintiffs’ scientific evidence, cross-examine their experts, introduce competing expert testimony, and argue that the available research does not establish that prenatal acetaminophen exposure causes autism or ADHD.

Ultimately, a jury may be asked to decide which scientific evidence is more persuasive.

The difference is that hundreds of families once again have the opportunity to move their cases forward.

What Happens to the Tylenol Autism Lawsuits Now?

The cases will return to Judge Cote in the Southern District of New York for further proceedings.

There is no settlement agreement, settlement fund, or scheduled Tylenol autism trial at this time.

The court will need to determine how the litigation proceeds following the Second Circuit’s decision.

The next stages could include additional discovery, depositions of expert witnesses and corporate representatives, challenges involving case-specific causation, dispositive motions, and eventually the selection of representative cases for trial.

Individual plaintiffs will still face significant challenges.

Even if the plaintiffs establish that prenatal acetaminophen exposure is capable of contributing to autism or ADHD, each family will eventually need evidence supporting specific causation.

Specific causation addresses whether acetaminophen exposure contributed to a particular child developing autism or ADHD.

The defendants may challenge whether the mother used acetaminophen during pregnancy, the amount and duration of exposure, the timing of that exposure, the child’s diagnosis, genetic factors, maternal illnesses, fever, infections, family medical history, and other possible explanations for the child’s condition.

However, the July 13 decision removed the biggest obstacle that had prevented hundreds of federal Tylenol lawsuits from moving forward.

Before the ruling, the plaintiffs had no admissible experts supporting their general causation theory and hundreds of cases had been dismissed.

Three of those experts can now testify.

For the first time since the federal cases were dismissed, plaintiffs once again have a path toward discovery, individual case development, and potentially presenting their claims to juries.

Dolman Law Group Has Been Involved in the Tylenol Autism Litigation From the Beginning

Dolman Law Group began investigating claims involving prenatal acetaminophen exposure and autism or ADHD before the federal Tylenol litigation was consolidated into multidistrict litigation.

We became one of the first law firms representing families pursuing these claims and have represented a significant number of mothers and children affected by the litigation.

Our attorneys have continued working with families throughout the federal Tylenol litigation, the exclusion of the plaintiffs’ experts, the dismissal of hundreds of lawsuits, the Second Circuit appeal, and the expansion of Tylenol autism and ADHD claims into state courts.

When the federal cases were dismissed, we did not assume the litigation was over.

We continued evaluating claims, monitoring the appeal, and participating in efforts to pursue Tylenol autism and ADHD lawsuits in state courts, including Florida, Illinois, and Pennsylvania.

The Second Circuit’s July 13, 2026 decision has now changed the trajectory of the federal litigation.

More than 500 lawsuits have been revived, three of the plaintiffs’ most important causation experts can once again present their opinions, and the cases will return to the Southern District of New York for further proceedings.

There is still a long way to go.

Plaintiffs must continue developing evidence of acetaminophen exposure, autism or ADHD diagnoses, general causation, and specific causation. The defendants will continue aggressively challenging the scientific evidence and individual claims.

Our attorneys will continue monitoring the federal litigation, participating in state court cases, evaluating potential claims, and providing families with updated information as the Tylenol autism lawsuits move forward.

Contact Dolman Law Group About a Tylenol Autism or ADHD Lawsuit

If you used Tylenol or another acetaminophen product during pregnancy and your child was later diagnosed with autism spectrum disorder or ADHD, you may have questions about whether your family can pursue a lawsuit.

The Second Circuit’s July 13, 2026 decision revived more than 500 federal lawsuits, but it does not mean every family with an autism or ADHD diagnosis will qualify to file a claim.

Our attorneys can review when and how frequently you used acetaminophen during pregnancy, your child’s diagnosis and medical history, available medical records, proof of acetaminophen use, and other factors that may affect your case.

Dolman Law Group offers free consultations to families seeking information about Tylenol, autism, and ADHD lawsuits. There are no upfront fees to have us review your potential claim, and you do not pay attorney fees unless we obtain compensation for you.

Dolman Law Group has extensive experience representing consumers in complex product liability and mass tort litigation involving some of the largest corporations in the country. Our attorneys have the resources, scientific consultants, and litigation experience necessary to evaluate claims involving complicated medical and causation issues.

Contact us today to speak with a Tylenol autism lawyer about your family’s potential case.

For continuing developments, visit our Tylenol autism lawsuit updates page on Lawsuit Legal News.