Trump gave medical advice about Tylenol. Here’s what medical experts say.

Punctuating his words with hand gestures, President Donald Trump on Monday warned pregnant women against using acetaminophen, the active ingredient in Tylenol, suggesting a connection between the widely used medication and autism.

“Don’t take Tylenol, don’t take it,” Trump said. “Fight like hell not to take it.”

He repeated the “don’t take Tylenol” refrain or slight variations of that at least 10 times during a wide-ranging White House briefing that also touched on vaccines and obesity medications, as well as the promise of a decades-old drug that could become the first treatment for the underlying causes of autism.

He acknowledged that his advice, which is largely unproven, represents his personal views.

Here’s what science and medical experts have to say about his words.

Tylenol is a brand name for the drug called acetaminophen, known outside the United States as paracetamol. One of the world’s most widely used over-the-counter medications, it is taken for temporary pain relief or to reduce fever.

Tylenol was first introduced by McNeil Laboratories in 1955 as an aspirin-free pain reliever for children, available with a prescription. Johnson & Johnson acquired McNeil in 1959, and soon after adult Tylenol was launched as an over-the-counter medication.

Tylenol executives have met with Trump administration officials in recent weeks to discuss the federal effort to investigate the role of acetaminophen in autism.

There are more than 600 other medications — prescription and otherwise — that contain acetaminophen, according to the FDA. Over-the-counter cough and cold medication, flu treatments, pain relievers and fever reducers, some allergy medicines and sleep aids can contain acetaminophen.

The recent interest in acetaminophen — picked up and accelerated by anti-vaccine, right-wing and MAHA influencers — was sparked by a study funded by the National Institutes of Health that was published Aug. 14 in BMC Environmental Health.

The study, led by researcher Diddier Prada of the Icahn School of Medicine at Mount Sinai and colleagues at Harvard’s T.H. Chan School of Public Health, involved a rigorous review of 46 previously published epidemiological studies. Of these, 27 reported links between use of the medication by pregnant women and an increased risk of autism or ADHD in their children, 9 showed no link and 4 indicated protective effects. The higher-quality studies were more likely to show a connection.

The findings, Prada emphasized, do not prove a causal link. “We show that acetaminophen is associated with a higher risk, but not causing it. Those are very different things,” he said in an interview with the Washington Post earlier this month.

That study investigated the use of acetaminophen during pregnancy and children’s risk of autism, ADHD and intellectual disability in nearly 2.5 million children in Sweden.

One of the co-authors, Brian Lee, a professor of epidemiology at Drexel University’s Dornsife School of Public Health, said that while researchers initially found a small statistical association using standard methods, that association “completely went away” when they conducted a sibling analysis examining children born to the same mother.

“This sibling analysis indicated that the statistical association that was observed using standard methods was attributable to other factors. In particular, we highlight genetic confounding … as a likely culprit,” Lee said via email.

At the news conference Monday, Trump said there was “no downside” in not taking Tylenol, and he repeatedly warned pregnant women to only use the medication if they had a high fever or felt they “can’t tough it out.”

If there is a link between acetaminophen and autism, it’s still unclear whether the risk comes from the drug itself or from the underlying conditions — such as fever, pain or inflammation — that lead people to use it. Doctors also worry that if a fever isn’t treated it could create stress on the fetus.

Cynthia Gyamfi-Bannerman, the past president of the Society for Maternal-Fetal Medicine and professor of maternal-fetal medicine at UC San Diego Health Sciences, said the concerns about autism and Tylenol have overshadowed well-established risks of untreated fevers in pregnancy.

“If you don’t take Tylenol when you have a fever, especially in the first trimester, we know that is detrimental to the fetus,” Gyamfi-Bannerman said.

“Suggestions that acetaminophen use in pregnancy causes autism are not only highly concerning to clinicians but also irresponsible when considering the harmful and confusing message they send to pregnant patients, including those who may need to rely on this beneficial medicine during pregnancy,” a statement from the American College of Obstetricians and Gynecologists said.

“Today’s announcement by HHS is not backed by the full body of scientific evidence and dangerously simplifies the many and complex causes of neurologic challenges in children. It is highly unsettling that our federal health agencies are willing to make an announcement that will affect the health and well-being of millions of people without the backing of reliable data.”

According to the Centers for Disease Control and Prevention, over-the-counter cold and cough medications are not recommended for children under age 6 as they can cause serious and sometimes life-threatening side effects. However, the agency said young children can be given acetaminophen or ibuprofen to reduce fever, adding that individuals should consult their health care providers for correct dosage.

The Caribbean island nation has faced a deepening public health crisis in recent years, including medicine shortages, which Cuban officials have partially attributed to years of U.S. sanctions. The CDC advises travelers to Cuba to bring with them medication such as over-the-counter acetaminophen or ibuprofen.

A 2017 paper published in MEDICC Review, a peer-reviewed journal focused on Caribbean and Latin American medicine, cited estimates from Cuba’s Ministry of Public Health that 1 in 2,500 Cuban children had been diagnosed with autism — though the ministry said the figure was likely an undercount.

Trump also claimed that the Amish have “essentially no autism.” But a 2010 paper presented at the International Society for Autism Research conference by researchers from schools including the University of Miami identified the presence of autism among the community and said further study was needed to ascertain whether cultural norms played a role in how it was reported by caregivers.

A letter from the Food and Drug Administration that is being sent out to doctors offers a more nuanced take. It clearly states that there’s no clear causal link. However, it continues, in the “spirit of patient safety and prudent medicine” clinicians should consider minimizing use of acetaminophen during pregnancy for routine low-grade fevers.

Kenvue’s statement: “We believe independent, sound science clearly shows that taking acetaminophen does not cause autism. We strongly disagree with any suggestion otherwise and are deeply concerned with the health risk this poses for expecting mothers.”

Conflicting guidance can be confusing, especially when some of the advice is coming from the president of the United States. Medical professionals say that acetaminophen is generally safe for use during pregnancy but advise pregnant individuals to speak with their doctors to determine what’s best.