Trump told pregnant women in September 2025 to avoid Tylenol because taking it would increase their babies' risk of autism: "Taking Tylenol is not good — I'll say it: It's not good."

Doctors and scientists quickly said the data didn't support the president's claim, but emergency room orders for Tylenol, or acetaminophen, for pregnant patients went down 10% in the months that followed, according to a new study in The Lancet. There was no change in the acetaminophen orders for comparable women who weren't pregnant.

"It happened overnight," says Dr. Jeremy Faust, an emergency physician at Brigham and Women's Hospital in Boston who led the study. The president's words "had an immediate impact on how much Tylenol or acetaminophen was being ordered in emergency departments."