Updated September 23, 2025 at 2:33 PM CDT
President Trump's suggestion that a link exists between autism and acetaminophen — the active ingredient in Tylenol — has raised concerns within the scientific community.
Trump, along with Health Secretary Robert F. Kennedy Jr. and Centers for Medicare and Medicaid chief Dr. Mehmet Oz, said Monday that autism rates are up because pregnant women are taking the medicine that is often used to treat pain and fever.
"Taking Tylenol is not good," Trump said during an announcement in which he also discouraged giving the medicine to young children. Tylenol's maker, Kenvue, told NPR in a statement that "independent, sound science clearly shows that taking acetaminophen does not cause autism. We strongly disagree with any suggestion otherwise and are deeply concerned about the health risks and confusion this poses for expecting mothers and parents."
Helen Tager-Flusberg, director of the Center for Autism Research Excellence (CARE) at Boston University and founder of the Coalition of Autism Scientists, called the administration's announcement "appalling." She said it was "a very significant distortion" of what science says about any possible links between acetaminophen and autism.
The message "is likely to impact millions of lives of pregnant women right now. Mothers of autistic children who are going to be so fearful that this is what they did to cause their child's autism, which is absolutely not the case," Tager-Flusberg said.
Speaking to NPR's Michel Martin, Tager-Flusberg, who has studied autism for decades, responded to claims Trump made about autism, acetaminophen and vaccines, and the FDA's move to label leucovorin as a treatment option for autism.
Genetics play a larger role in autism
At the White House Monday, Trump said pregnant patients should "fight like hell not to take [acetaminophen]." He continued saying: "There may be a point where you have to and that – you'll have to work out with yourself. So don't take Tylenol."
A study released in August by Harvard University found that women who said they took acetaminophen while pregnant seemed more likely to have a child diagnosed with autism. Ann Bauer, an epidemiologist who worked on that study, told NPR she worried it was too soon for the federal government to offer guidance and that the research community needed to see more evidence.
Tager-Flusberg said that if there is an association between acetaminophen and autism, it is "small" and "limited" and "interacts most likely with the genetics, which is the main contribution to what causes autism."
She added, "There's absolutely no evidence out there to support the kind of strong statement that we heard from President Trump."
There is no link between the autism and the measles, mumps and rubella vaccine
Tager-Flusberg said the combination MMR vaccine (measles, mumps and rubella) — which Trump also took aim at Monday — is "perfectly safe" and that research has completely debunked any links between it and autism. Study after study have found no link between autism and the vaccine, which is typically administered to children after their first birthday and again between ages 4 and 6, according to the CDC.
On Monday, Trump suggested splitting the MMR vaccine's administration into multiple visits.
"Don't let them pump your baby up with the largest pile of stuff you've ever seen in your life, going into the delicate little body of a baby, even if it's two years, three years, four years, you just break it up into, I would say five, but let's say four, four visits to the doctor instead of one."
Tager-Flusberg said Trump raising the concern is "likely to raise fear among mothers, confusion and chaos for pediatricians."
"This is really not what our society needs right now," she added.
Is leucovorin a valid treatment for speech deficiencies caused by autism?
The Food and Drug Administration also announced Monday that it would label leucovorin, a form of vitamin B typically used along with cancer medicines, as a treatment for speech-related deficits associated with autism.
Tager-Flusberg said that while a "promising" small-scale study showed language improvement for a group of children who were administered leucovorin, the treatment has — at best — "weak evidence in support of it."
She added that researchers need to build on early studies with a large-scale, randomized controlled trial and that they need to know what outcomes can be expected, dosage levels and which children to observe.
"We need a study to investigate this right now, far before the FDA … should be approving this medication," Tager-Flusberg said. "They haven't done this for a single other medication in the history of autism."
This digital story was edited by Majd Al-Waheidi. The radio story was edited by Adriana Gallardo and produced by Mansee Khurana.
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