Does Tylenol Cause Autism? What the Evidence Shows

Does Tylenol cause autism? No: the best current evidence does not show that taking Tylenol (acetaminophen, called paracetamol outside the US) during pregnancy causes autism. Earlier studies found a small statistical link, but large studies that compare brothers and sisters from the same family find that the link disappears, which points to shared genes and family factors rather than the medicine.

This Myth of the Week explains where the claim came from, what the strongest studies show, why it is still in the news, and how it affects autistic people and their families. It is not medical advice: anyone pregnant should talk to a health professional about pain or fever.

Key takeaways

A 2024 JAMA study of nearly 2.5 million children born in Sweden found no link between acetaminophen in pregnancy and autism when siblings were compared.
A January 2026 systematic review in The Lancet Obstetrics, Gynaecology & Women’s Health, covering 43 studies, found no increased risk of autism, ADHD or intellectual disability.
A July 2026 sibling study in JAMA Internal Medicine, using Hong Kong health records, also found no association with autism or ADHD.
The US Food and Drug Administration (FDA) said in September 2025 that “a causal relationship has not been established”, even as it started a label-change process.
A July 2026 US appeals court ruling allowed lawsuits to continue but explicitly did not decide whether acetaminophen causes autism.

Where does the claim that Tylenol causes autism come from?

Over the past decade, several observational studies reported that children whose mothers used acetaminophen in pregnancy were slightly more likely to be diagnosed with autism or ADHD. Observational studies can show that two things happen together, but they cannot by themselves show that one causes the other.

The claim became global news on 22 September 2025, when the US government linked acetaminophen in pregnancy to autism at a White House event. On the same day, the FDA announced it would start the process of changing the drug’s label, while also stating that “a causal relationship has not been established and there are contrary studies in the scientific literature” (FDA).

The government cited, among other work, a 2025 review in the journal Environmental Health led by researchers at Mount Sinai and Harvard, which argued the evidence was consistent with an association (Mount Sinai). Other scientists disagreed, mainly because many of the studies it included could not separate the effect of the medicine from family and genetic factors.

What does the evidence show about acetaminophen in pregnancy and autism?

The strongest studies use a sibling comparison. They look at mothers who took acetaminophen in one pregnancy but not another, and compare those children. Because siblings share much of their genes and home environment, this design removes many hidden factors that can create a false link.

Sweden: 2.5 million children

A 2024 study in JAMA, led by Viktor Ahlqvist at Karolinska Institutet, followed 2,480,797 children born in Sweden between 1995 and 2019. In the standard analysis, there was a tiny increase in autism risk (hazard ratio 1.05). In the sibling comparison it disappeared (hazard ratio 0.98), suggesting the earlier link came from other factors (JAMA, via PubMed Central). Limitations include incomplete data on dose, timing and over-the-counter use.

A review of 43 studies

In January 2026, a systematic review and meta-analysis in The Lancet Obstetrics, Gynaecology & Women’s Health, co-authored by Professor Asma Khalil of City St George’s, University of London, pooled 43 studies and gave most weight to high-quality sibling studies. It found no link with autism, ADHD or intellectual disability (City St George’s; STAT). The authors could not analyse results by trimester or by how often the drug was taken.

Hong Kong: a different population, the same result

A July 2026 study in JAMA Internal Medicine, led by Shan Luo at the University of Hong Kong, used health records starting from 708,020 mother–child pairs. In sibling-matched analyses, the odds ratio for autism was 1.00, meaning no increased risk (JAMA Internal Medicine; PsyPost). It relied on prescription records, so it could miss medicine bought over the counter.

Why do some studies find a link?

The most likely answer is confounding, which means a third factor explains both things. Autism is highly heritable, and parents who are autistic or have related traits, chronic pain, migraines or infections may use pain relief more often. Their children may be more likely to be autistic because of shared genes, not because of the medicine.

Fever and infection in pregnancy, which acetaminophen is often used to treat, are also being studied as possible factors in their own right. Researchers agree more work is needed on dose and timing, but no high-quality study so far shows that acetaminophen causes autism.

Why is the Tylenol autism claim still in the news?

Two things keep the story alive. First, on 13 July 2026, the US Court of Appeals for the Second Circuit revived more than 500 lawsuits against Kenvue, the maker of Tylenol, by allowing expert witnesses that a lower court had excluded. The judges stressed they were “not deciding whether using acetaminophen causes autism or ADHD” (Claims Journal / Reuters). A court allowing a case to go ahead is not a scientific finding.

Second, as of September 2026 the FDA label had not actually changed; it still tells pregnant people to ask a health professional before use (Medical Daily). Meanwhile, misinformation spread widely online: a study presented in October 2026 found misleading TikTok videos on the topic drew more than half the views in its sample (Contemporary Pediatrics).

How does this myth harm autistic people and families?

It blames mothers. Parents of autistic children are told, without evidence, that a common painkiller they took “caused” their child’s autism, adding guilt where none is warranted.
It can put pregnant people at risk. Untreated high fever and severe pain in pregnancy carry their own risks, and alternatives such as ibuprofen are generally not advised in later pregnancy. A 2026 report noted acetaminophen prescribing to pregnant patients in US emergency departments fell after the announcement.
It frames autism as damage. Searching for a pill to blame treats autistic people as a preventable mistake rather than as people with rights and needs.
It distracts from support. Time and money spent on disproven causes are not spent on assessment, education, adult services and mental health care.

Many autistic people point out that autism has always existed, and that better recognition explains much of the rise in diagnoses, especially among women diagnosed late. See our other myths vs evidence explainers and research summaries.

FAQ

Does Tylenol cause autism?

Current evidence says no. Large sibling-comparison studies from Sweden and Hong Kong, and a 2026 review of 43 studies, found no increased risk of autism after accounting for family and genetic factors.

Is acetaminophen safe to take during pregnancy?

Major medical bodies, including the American College of Obstetricians and Gynecologists, continue to describe acetaminophen as an appropriate option for pain and fever in pregnancy when used as directed. Decisions about medicine in pregnancy should be made with a health professional.

Did a court rule that Tylenol causes autism?

No. In July 2026, a US appeals court allowed expert evidence and lawsuits to proceed, but the judges said explicitly that they were not deciding whether acetaminophen causes autism.

Why did the FDA change the Tylenol label?

In September 2025 the FDA started a process to update the label, while saying a causal link had not been established. As of September 2026, the official label had not changed.

Sources

This post was prepared with AI assistance and reviewed by the OtizmTV editorial team.

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Does Tylenol Cause Autism? What the Evidence Says About Pregnancy Use