Shares of Tylenol maker Kenvue plunged on Friday, September 5, 2025, after reports emerged that U.S. Health Secretary Robert F. Kennedy Jr. intends to link the popular pain reliever to autism in an upcoming federal report. The controversy comes amid longstanding debates about the causes of autism, the safety of common medications during pregnancy, and the reliability of public health leadership at a time when trust in institutions is already under strain.
According to BBC, Kenvue’s stock tumbled as much as 14% before closing the day down 9.5%, following a Wall Street Journal report that Kennedy’s forthcoming analysis would cite Tylenol use during pregnancy as a potential cause of autism. The report, expected later in September, may also recommend a specific form of folate, known as folinic acid, as a treatment for autism symptoms. The news sent ripples through the pharmaceutical world and reignited a fierce medical controversy that has simmered for years.
“Nothing is more important to us than the health and safety of the people who use our products,” a Kenvue spokesperson told the Wall Street Journal. “We have continuously evaluated the science and continue to believe there is no causal link between acetaminophen use during pregnancy and autism.” The company noted that leading medical organizations agree on the safety of acetaminophen, the active ingredient in Tylenol, and its use during pregnancy. Kenvue also advised expectant mothers to consult healthcare professionals before taking any over-the-counter medication, including acetaminophen.
Acetaminophen, known as paracetamol in the UK, is one of the most widely used pain relievers and fever reducers worldwide. In the United States, doctors routinely recommend Tylenol for pregnant women who require pain relief, as alternatives like ibuprofen are considered riskier during pregnancy. Researchers have long noted that untreated maternal fever and pain can themselves pose risks to developing fetuses, adding complexity to the debate.
The controversy over Tylenol’s safety during pregnancy is not new. Some studies have found associations between prenatal acetaminophen exposure and an increased risk of neurodevelopmental disorders such as autism spectrum disorder and ADHD. For example, a review published last month by researchers from the Icahn School of Medicine at Mount Sinai and Harvard’s T.H. Chan School of Public Health analyzed 46 epidemiological studies: 27 reported links between acetaminophen use during pregnancy and increased risk of neurodevelopmental disorders, nine found no significant association, and four suggested possible protective effects. In 2021, an international group of 91 scientists and clinicians issued a consensus statement urging caution in the use of acetaminophen during pregnancy.
However, the largest and most comprehensive studies have failed to confirm a causal relationship. As The Hill and Axios report, a 2024 study published in the Journal of the American Medical Association followed more than 2.4 million children born in Sweden. The researchers found no evidence that acetaminophen use during pregnancy was associated with autism, ADHD, or intellectual disability in sibling control analyses. They concluded that associations observed in other models may be explained by confounding factors, including genetics. The American College of Obstetricians and Gynecologists (ACOG) has also stated, “There is no clear evidence that proves a direct relationship between the prudent use of acetaminophen during pregnancy and fetal developmental issues.”
Dr. Nathaniel DeNicola, an OB-GYN advising ACOG, told the New York Times that the conclusion of the recent review is that Tylenol should be used judiciously, at the lowest dose and least frequent interval—"exactly the current standard of care for Tylenol." The U.S. Food and Drug Administration (FDA) echoes this advice on its website, recommending that pregnant women consult their doctors before using acetaminophen, as with all medicines.
Despite the lack of clear scientific consensus, hundreds of lawsuits have been filed in U.S. courts alleging that Tylenol caused autism and other neurodevelopmental disorders in children. As BBC notes, last August a federal judge dismissed all such cases, determining that the plaintiffs’ expert witnesses lacked sufficient scientific evidence. The ruling is currently being appealed.
Amid the legal and scientific wrangling, Health Secretary Kennedy has amplified the debate. According to Axios, Kennedy’s upcoming report is also expected to highlight folinic acid (leucovorin), a form of folate, as a possible treatment to decrease autism symptoms. While some studies suggest that certain forms of folate can improve communication and language skills in some children with autism, the evidence remains limited and inconclusive.
The Department of Health and Human Services (HHS) responded to the speculation with caution. “We are using gold-standard science to get to the bottom of America’s unprecedented rise in autism rates. Until we release the final report, any claims about its contents are nothing more than speculation,” an HHS spokesperson told BBC. The agency emphasized that the report is still being finalized and that any public discussion of its findings is premature.
FDA commissioner Marty Makary echoed this sentiment during a Friday appearance on NewsNation’s “The Hill.” “The report is not written, so there’s nothing really to report, because we’re still in our discussions,” Makary said, referencing recent studies from Harvard and Duke that have fueled renewed interest in the Tylenol-autism question. “We are incredibly data driven, so we’re looking at the Harvard study and the other study out of Duke, and we’re trying to analyze the magnitude and the weight of that data. But that is not the primary focus of this report.” Makary added that the president and Kennedy have made autism research a “national priority” and that a comprehensive report is expected later in September.
Kennedy’s leadership and views have drawn sharp scrutiny in recent weeks, particularly in light of his longstanding skepticism regarding vaccines. Eleven of the twelve Democrats on the Senate Committee on Finance have called for Kennedy’s resignation, as have two of his family members. Republican lawmakers, including Senate Republican Whip John Barrasso, have also criticized Kennedy’s rhetoric. “I support vaccines. I’m a doctor. Vaccines work,” Barrasso asserted at a recent hearing, expressing concern about Kennedy’s approach to public health.
The uncertainty has been compounded by recent turmoil at the Centers for Disease Control and Prevention (CDC), where Director Susan Monarez was unexpectedly removed and four senior officials resigned. Lawmakers have raised questions about internal policies and practices under Kennedy, with Barrasso warning, “Americans don’t know who to rely on. If we’re going to make America healthy again, we can’t allow public health to be undermined.”
Autism now affects an estimated one in 31 American children, according to the CDC. Scientists attribute at least part of the rise to increased awareness and broader diagnostic criteria, though environmental factors remain under investigation. As the nation awaits the release of Kennedy’s report, the debate over Tylenol’s safety, the causes of autism, and the future of public health policy continues to unfold—leaving parents, doctors, and policymakers searching for clarity amid a sea of conflicting claims and scientific uncertainty.
