In September 2025, President Trump and Health Secretary Robert F. Kennedy Jr. urged pregnant women at a White House announcement to avoid taking Tylenol (acetaminophen), saying it could raise their babies’ risk of autism. Scientists and doctors quickly said the evidence did not support that claim.
A new study published in The Lancet found that emergency department orders for acetaminophen for pregnant patients fell about 10% in the months after the announcement. There was no corresponding change in acetaminophen orders for similar patients who were not pregnant. The researchers analyzed electronic health records from more than 1,600 hospitals.
“This happened overnight,” says Dr. Jeremy Faust, an emergency physician at Brigham and Women’s Hospital in Boston who led the study. He said the president’s remarks had an immediate impact on how much Tylenol was ordered in emergency departments. The study could not determine whether patients declined the drug or clinicians prescribed it less; Faust says it was likely a mix of both.
Dr. Caleb Alexander, an epidemiology professor at Johns Hopkins Bloomberg School of Public Health, said the finding was not surprising: “Words matter,” and statements from high-profile leaders can change prescriber and patient behavior. He noted it is reassuring that acetaminophen use was returning toward normal by December, and that lasting changes in prescribing typically require more than a single event.
The study also found a sharp rise in prescriptions for leucovorin, a B vitamin the president suggested as an autism treatment; those prescriptions had not fallen by the end of the study period in early December. There have not been large clinical trials proving leucovorin’s efficacy for autism.
Tylenol maker Kenvue said it stands with science and that there is no credible evidence proving a link between acetaminophen and autism. The company reported that Tylenol consumption “improved” in December, and while the president and his health team spoke about updating Tylenol’s label, no such label change has occurred.
