A number of posts discussed Trump's support for the discredited notion. The Monday White House news conference was a firehose of lies.
Health Secretary Robert F. Kennedy Jr.’s team had decided by the beginning of September to tell Americans that acetaminophen, the active ingredient in Tylenol, was a possible cause of autism. But officials were divided over how much emphasis to put on the painkiller and were planning to discuss it as one of many possible causes, people familiar with the matter said.
Doctors that Kennedy had selected to lead key agencies under him—Jay Bhattacharya, Mehmet Oz and Marty Makary—suggested the big story should be leucovorin, a little-known generic drug in which they saw promise for alleviating autism symptoms.
But a meeting with Tylenol’s maker convinced Kennedy to put the emphasis on acetaminophen.
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The result was the explosive White House news conference Monday, when the president laid out in no uncertain terms that pregnant women should avoid Tylenol (“Don’t take it”), despite the mixed evidence linking the painkiller to autism. The event stunned many of the nation’s doctors and public health experts, some of whom called Trump’s actions dangerous.
In the end, Trump and Kennedy went with their own messaging instincts, and leucovorin became more of an afterthought. Trump didn’t mention it by name at the press conference, giving only a passing mention to a new label for “an existing drug” that may help alleviate autism symptoms. “That’s one of the things that I’m very, very happy about,” he said.
The elderly Trump struggled to pronounce "acetaminophen" and probably did not want to try "leucovorin."
“Ah-ced-uv — well, let’s see how we say that.”
— The Recount (@therecount) September 22, 2025
— Trump butchers pronunciation of acetaminophen while announcing his admin is falsely linking it to autism pic.twitter.com/5rwUnDYMCC
According to Martin Makary, head of the US Food and Drug Administration (FDA), the drug leucovorin will help “hundreds of thousands of kids” with autism. But a day after Makary praised leucovorin’s powers at a White House event, some specialists are warning that the science to warrant Makary’s enthusiasm is far from solid.
Those researchers say that the drug’s efficacy has not been established, that scientists don’t know how much of the drug to give or how people should take it, and that safety data in children are lacking. According to the FDA’s current plans, leucovorin will be available to only a minority of autistic people.
All of this has led to widespread confusion, say clinicians, who also worry about the expectations created by Makary and other officials in the administration of US president Donald Trump.
“I’ve heard from a lot of families,” says psychologist Catherine Lord at the University of California, Los Angeles. “The major thing they say is, ‘What is this? What do we do?’”
“I don’t want to get everyone’s hopes up that this is a magic cure,” says Rebecca Schmidt, a molecular epidemiologist at the University of California, Davis. “It’s not for everybody.”
Jon Hamilton Yuki Noguchi at NPR:
"It's a bit tough to get really, really excited about what they would call a 'miracle drug,'" says Shelby Smith, a Dallas mother of a 6-year-old autistic son who is considered non-verbal. Parents, she says, are accustomed to being peddled vitamins, supplements, and even fake therapies. "It's always something being pushed," Smith says, which can at times then make symptoms worse.
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Given the lack of conclusive evidence, many doctors and researchers think it's too soon to be suggesting leucovorin as a treatment.
"They are jumping the gun a little bit," says Alycia Halladay, a biopsychologist and chief science officer of the Autism Science Foundation.
The Coalition of Autism Scientists issued a statement saying, "It is premature to claim that leucovorin is an effective treatment for autism."
Medical and scientific groups say they'd like to see the same sort of research on leucovorin that the FDA requires of other drugs: two large, rigorous clinical trials showing that the product lives up to its label.
