Health Secretary Robert F. Kennedy Jr. and other officials announced on Sept. 22 that acetaminophen, the active ingredient in Tylenol, may be associated with autism, a disorder with a wide range of symptoms. They also said that leucovorin, or prescription folinic acid, looks like a promising therapy for autism.
Here’s what to know about the new announcement, autism, and folinic acid.
Tylenol Link
Officials said the available evidence regarding a link between acetaminophen, also known as paracetamol, and neurodevelopmental disorders is sufficient to issue a new warning against using acetaminophen during pregnancy.
“We now have data we cannot ignore,” Dr. Marty Makary, the Food and Drug Administration’s commissioner, told a briefing in Washington.
That includes a 2019 study from Boston University and Johns Hopkins University School of Medicine that analyzed umbilical cord plasma and determined that in-utero exposure to acetaminophen heightened the risk of developing autism and attention-deficit/hyperactivity disorder (ADHD), two neurodevelopmental disorders.
A 2025 review also found “evidence consistent with an association between acetaminophen exposure during pregnancy and increased incidence” of neurodevelopmental disorders, according to Dr. Andrea Baccarelli, a dean at the Harvard TH Chan School of Public Health, and his coauthors.
In a notice to physicians dated Sept. 22, Makary said that “evidence has accumulated suggesting that the use of acetaminophen by pregnant women may be associated with an increased risk of neurological conditions such as autism and ADHD in children.”
He said that doctors should consider minimizing the use of acetaminophen during pregnancy, while being aware that it’s the safest over-the-counter medicine for fever and pain.
Other experts dispute that the evidence supports a link, pointing in part to a 2024 Swedish study that analyzed the records of nearly 2.5 million children and concluded there was no link between fetal acetaminophen exposure and the development of autism or ADHD.
“At this time, the weight of scientific evidence that acetaminophen use during pregnancy causes an increased risk for autism or ADHD is simply inconclusive,” Dr. Sindhu Srinivas, president of the Society for Maternal-Fetal Medicine, said in a recent statement. The organization said on Monday it is standing behind its recommendation that acetaminophen is safe to treat pain and fever in pregnant women.
A spokesperson for Kenvue, the parent company of Tylenol’s manufacturer, told The Epoch Times in an email on Sept. 22 that “over a decade of rigorous research, endorsed by leading medical professionals and global health regulators, confirms there is no credible evidence linking acetaminophen to autism.”ylenol Link
Officials said the available evidence regarding a link between acetaminophen, also known as paracetamol, and neurodevelopmental disorders is sufficient to issue a new warning against using acetaminophen during pregnancy.
“We now have data we cannot ignore,” Dr. Marty Makary, the Food and Drug Administration’s commissioner, told a briefing in Washington.
That includes a 2019 study from Boston University and Johns Hopkins University School of Medicine that analyzed umbilical cord plasma and determined that in-utero exposure to acetaminophen heightened the risk of developing autism and attention-deficit/hyperactivity disorder (ADHD), two neurodevelopmental disorders.
A 2025 review also found “evidence consistent with an association between acetaminophen exposure during pregnancy and increased incidence” of neurodevelopmental disorders, according to Dr. Andrea Baccarelli, a dean at the Harvard TH Chan School of Public Health, and his coauthors.
In a notice to physicians dated Sept. 22, Makary said that “evidence has accumulated suggesting that the use of acetaminophen by pregnant women may be associated with an increased risk of neurological conditions such as autism and ADHD in children.”
He said that doctors should consider minimizing the use of acetaminophen during pregnancy, while being aware that it’s the safest over-the-counter medicine for fever and pain.
Other experts dispute that the evidence supports a link, pointing in part to a 2024 Swedish study that analyzed the records of nearly 2.5 million children and concluded there was no link between fetal acetaminophen exposure and the development of autism or ADHD.
“At this time, the weight of scientific evidence that acetaminophen use during pregnancy causes an increased risk for autism or ADHD is simply inconclusive,” Dr. Sindhu Srinivas, president of the Society for Maternal-Fetal Medicine, said in a recent statement. The organization said on Monday it is standing behind its recommendation that acetaminophen is safe to treat pain and fever in pregnant women.
A spokesperson for Kenvue, the parent company of Tylenol’s manufacturer, told The Epoch Times in an email on Sept. 22 that “over a decade of rigorous research, endorsed by leading medical professionals and global health regulators, confirms there is no credible evidence linking acetaminophen to autism.”
Autism Rates Rise
Autism is a disorder with symptoms such as difficulty communicating and maintaining eye contact. About a quarter of autistic people cannot speak or are “minimally verbal,” according to a 2018 review of autism data.
Autism rates have spiked in the United States in recent decades.
The prevalence was one in 31 children in 2022, the Centers for Disease Control and Prevention said in the spring. That was up from one in 150 children in 2002.
President Donald Trump on Monday referenced older numbers indicating the rate was once much lower. With such a large increase, “you know there’s something artificial,” he said.
Kennedy said in April that genetics may be behind some cases, but with such a jump, “you need an environmental toxin.”
The CDC said previously on its website that a number of factors may make a child more likely to have autism, including being born to older parents and having certain genetic conditions.
Some groups, such as the Autism Society of America, say the increase may stem from updated diagnostic criteria and more recognition of the disorder.
“Increased awareness of Autism plays a pivotal role in educating individuals, parents, educators and healthcare providers to better identify Autistic traits and characteristics,” the group said in April. “This fact coupled with expanded diagnostic criteria over the past decade, leads to fewer misdiagnoses, and a broader interpretation of what falls within the spectrum.”
Vaccines a Cause?
Kennedy has in the past said vaccines can cause autism.
“Many of the parents have reported that their kid, that their child developed autism immediately after the vaccine—so that’s something that we’re looking at right now,” he said earlier this year.
On Monday, officials did not say that vaccines are a cause. But they did not rule out making such an announcement in the future.
“Autism is a complex disorder with multifactorial etiology,” Kennedy said. “We are continuing to investigate a multiplicity of potential causes, with no areas of taboo. One area that we are closely examining, as the president mentioned, is vaccines. Some 40 to 70 percent of mothers who have children with autism believe that their child was injured by a vaccine. President Trump believes that we should be listening to these mothers instead of gaslighting and marginalizing them.”
Some parents have reported that they believe autism can be caused by vaccines, including measles-mumps-rubella vaccination. Research into a possible link between that shot and autism has not found an association. However, under a government program, some people have been compensated for claims of injuries from vaccines, including autism.
Trump has voiced support for spacing out the administering of vaccines more than the current government schedule recommends.
“They pump so much stuff into those beautiful little babies,” he said on Monday, later criticizing the recommendation that babies receive a hepatitis B dose shortly after birth.
Advisers to the CDC were considering delaying the first dose of the hepatitis B vaccine, but decided on Sept. 19 to postpone the vote to gather more data. They did advise the CDC to update recommendations for COVID-19 vaccines to emphasize that people should consult with health care providers and consider various factors before receiving one of the shots.
The CDC also announced this month it was planning to award money to an institute to investigate “the association between vaccinations and autism prevalence,” as part of its new mission.
The National Institutes of Health, meanwhile, is awarding $50 million to 13 projects that will focus on the root causes of autism as well as therapies for the disorder.
“Scientists will use rigorous, advanced methods in causal inference, machine learning … and other fresh approaches to the problem,” Dr. Jay Bhattacharya, director of the National Institutes of Health, said at the briefing. “The sharp rise in the prevalence of autism deserves an urgent response by the scientific community.”
Folinic Acid Recommendation
Folic acid is a synthetic form of folate, while folinic acid is a natural form. Officials on Monday said that prescription folinic acid, or leucovorin, can help autistic people and their symptoms. They’re looking to approve a type of leucovorin called Wellcovorin, which was previously withdrawn, for people with cerebral folate deficiency, including some autistic people.
“Hundreds of thousands of kids, in my opinion, will benefit,” Makary said at the briefing.
Several randomized, placebo-controlled trials have found amelioration of autism symptoms in folinic acid recipients. Autistic people in an American trial experienced improvement in verbal communication, as described in a 2016 paper. Participants in a French trial recorded better scores in the Autism Diagnostic Observation Schedule, an assessment of autism symptoms. And autistic children who received folinic acid in a trial in India saw better scores in a similar rating system.
Researchers have also identified a high prevalence of folate receptor autoantibodies, which interfere with the transport of folate inside the body, in some autistic individuals.
Folinic acid “gets around that blocked receptor—it can be transported into the brain and is already in a usable form,” Dr. David Danish, a psychiatrist and president of Philadelphia Integrative Psychiatry, told The Epoch Times in an email.
Most of Danish’s patients who received folinic acid have shown meaningful gains, often within days or weeks, he said. Danish also said that leucovorin won’t help everyone, “but for those with impaired brain folate transport, it’s a logical, evidence-based option that’s delivering real clinical gains in autism and other conditions.”
Autism Speaks, a group that advocates for autistic individuals, said in a statement that “leucovorin shows promise in improving speech in minimally verbal children” but “larger, well-controlled clinical trials are still needed to confirm its efficacy and safety as a therapeutic treatment.”
Dr. Richard E. Frye, who conducted some of the trials and recently wrote a book called “The Folate Fix,” told The Epoch Times in an email that the scientific evidence supports using folinic acid.
“This is a safe, well-tolerated treatment which can improve lives of many individuals with autism,” he said. “It is not a cure, but improves the function of many children substantially.”
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