US President Donald Trump on Monday urged pregnant women to avoid Tylenol, claiming the widely used pain reliever could be linked to autism. Tylenol, known generically as acetaminophen in the US and as paracetamol in other countries, is one of the most common medicines for fever and mild pain.

“Don’t take Tylenol,” Trump told reporters at the White House, also advising parents not to give it to infants. He said his administration was connecting acetaminophen with autism and would soon notify doctors about the risk.

The comments immediately drew criticism from medical experts, who called the claim unproven and potentially harmful. Dr. David Mandell, an autism expert at the University of Pennsylvania, noted that while some studies have suggested a possible link between acetaminophen use in pregnancy and autism, many others have found no evidence.

The American College of Obstetricians and Gynecologists called Trump’s remarks “irresponsible,” while the American Academy of Pediatrics said spreading doubt about safe medications and vaccines threatens children’s health.

According to the Society for Maternal-Fetal Medicine, acetaminophen is often the safest option to treat high fevers in pregnancy, since untreated fever can itself cause complications like miscarriage or preterm birth.

Tylenol is manufactured by Kenvue, the consumer health company that owns brands like Johnson’s, Listerine and Neutrogena.

The company dismissed Trump’s claims, warning that pregnant women would face dangerous choices if forced to avoid Tylenol.

Still, Kenvue’s shares fell 7.5% on Monday, wiping out about $2.6 billion in market value. 

Trump also revived his long-standing criticism of vaccines, echoing arguments made by health secretary Robert F Kennedy Jr, whose “Make America Healthy Again” campaign has pushed for scrutiny of autism rates.

Medical leaders insist that autism develops in the fetal brain and is not caused by childhood vaccines or common medicines like Tylenol.