Tylenol maker Kenvue Inc. saw its share price plummet on Monday, as President Donald Trump linked use of the painkiller by pregnant women with a "meteoric rise" in autism among children.
Shares of the New Jersey-based company sank 7.5 percent on Monday, but are up around six percent in pre-market trading on Tuesday at the time of writing.
Kenvue has already stated that it "strongly disagrees" with the Trump administration's announcement, and that "sound science" shows no connection between acetaminophen, Tylenol’s active ingredient, and autism.
Why It Matters
Tylenol, known outside the U.S. as paracetamol, is the world's most widely used over-the-counter pain and fever medication. The drug is considered by doctors a safe form of pain relief, and is the first-choice painkiller for pregnant women.
Medical professionals have already pushed back on the link made by the Trump administration, calling it premature given the limited evidence and warning that this could deter women from using acetaminophen when needed during pregnancy.
What To Know
President Trump’s news conference, where he was flanked by Secretary of Health and Human Services Robert F. Kennedy Jr. and several federal officials, took place on Monday afternoon. The Washington Post, citing those with knowledge of the plans, reported earlier in the day that the administration was planning to make the announcement regarding Tylenol use. The Wall Street Journal published a similar report in early September, which again coincided with a sharp drop in Kenvue’s share price.
During the event, Trump called the rise in autism diagnoses "among the most alarming public health developments in history," citing 2022 figures from the Centers for Disease Control and Prevention (CDC) which found a one in 31 prevalence of the neurodevelopmental condition in the U.S.
The administration said it will soon advise U.S. doctors against prescribing Tylenol to pregnant women, while Kennedy said the Food and Drug Administration (FDA) plans to issue a notice to physicians about the potential risks of taking Tylenol during pregnancy, and "begin the process to initiate a safety label change."
Officials cited a recent review of studies examining the link between prenatal acetaminophen exposure and later neurodevelopmental disorders, which found an association. Epidemiologist Ann Bauer, one of the co-authors, told Newsweek that "more definitive studies" were needed to establish a direct causal link and that Tylenol remains the "best option" for some patients. However, she noted that "acetaminophen has many of the hallmarks of an environmental toxicant."
Prior to the official announcement, Bauer said that she was "a little concerned about how this message is going to come because I think they may be jumping the gun."
"I think those of us in the research community would like to see stronger evidence," she added.
Other research has challenged the connection, including a landmark 2024 study which compared siblings with and without exposure to acetaminophen in the womb, and found no significant correlation to autism or other neurodevelopmental disorders.
Jan Buitelaar, an expert in neuropsychiatry and developmental disorders at Radboud University Medical Centre in the Netherlands, told Newsweek that the evidence regarding a link "is very thin and inconsistent."
"The problem is that the association between acetaminophen use in pregnant women and later autism and ADHD may be confounded by all sorts of other factors (genetics, environmental factors, maternal infections etc.)," he added.
President Trump also suggested that autism is effectively nonexistent among Cubans and the Amish population thanks to them not using the medication, though various studies have disputed this.
What People Are Saying
Kenvue, in a statement shared with Newsweek, said: "Acetaminophen is the safest pain reliever option for pregnant women as needed throughout their entire pregnancy. Without it, women face dangerous choices: suffer through conditions like fever that are potentially harmful to both mom and baby or use riskier alternatives.
“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 about the health risks and confusion this poses for expecting mothers and parents.
“The facts are that over a decade of rigorous research, endorsed by leading medical professionals and global health regulators, confirms there is no credible evidence linking acetaminophen to autism. We stand with the many public health and medical professionals who have reviewed this science and agree.“
Claire Anderson, president of the United Kingdom’s Royal Pharmaceutical Society, told Newsweek: "Paracetamol has been used safely by millions of people for decades, including during pregnancy, when taken as directed. It is the first-line choice for pain management and fever control in a variety of patients, including pregnant women, children and the elderly."
"Anyone with concerns about their medicines should speak to a pharmacist or other trusted health care professional to ensure they are getting sound advice from a trusted source," she added.
Steven J. Fleischman, president of the American College of Obstetricians and Gynecologists, said in a statement: "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."
President Trump, during Monday’s news conference, said: "I’m going to say it like it is. Don’t take Tylenol. Don’t take it. If you just can’t—I mean—fight like hell not to take it. There may be a point where you have, and that you’ll have to work out with yourself."
Health Secretary Kennedy said: "Today, we are taking bold action—opening the door to the first FDA-recognized treatment pathway, informing doctors and families about potential risks, and investing in groundbreaking research. We will follow the science, restore trust, and deliver hope to millions of American families."
What Happens Next?
On Monday, Health Secretary Kennedy said the FDA would start exploring potential remedies for speech-related issues associated with autism, adding that the agency is preparing to approve leucovorin, also known as folinic acid, to be used as a treatment.
