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The dispute shines a light on the vulnerability of long-established drugs to renewed safety scrutiny: Even when causal evidence is lacking, observational findings can influence policy and public perception.
World autism awareness day April 2 - Studio Portrait of a cute asian boy cover his face with the colorful puzzles pieces. Autism Spectrum Disorder concept, ASD, Syndrome, Light it up blue, Backdrop. | Image Credit: © myboys.me - stock.adobe.com
On Sept. 22, 2025, the administration of US President Donald Trump took its most decisive steps yet in discouraging the ingestion of acetaminophen, most widely known under the brand name Tylenol, during pregnancy, saying there is mounting evidence of a connection between use of the pain-relief drug—especially late in pregnancy—and long-term neurological effects in children, including autism spectrum disorder and attention-deficit/hyperactivity disorder (ADHD) (1).
The same day, a Politico op-ed co-authored by three Trump administration officials—National Institutes of Health Director Jay Bhattacharya, MD, PhD; FDA Commissioner Marty Makary, MD; and Centers for Medicare & Medicaid Services Administrator Mehmet Oz, MD—outlined a series of three steps the administration is undertaking, including the Autism Data Science Initiative, intended to attempt to explain and come to a consensus on why autism rates in the United States continue to grow (2).
In both the White House statement and the op-ed, the Trump administration links to information from several sources that it says have documented “observational evidence” of a connection between acetaminophen use, particularly close to delivery, and subsequent diagnoses of autism, ADHD, and other conditions.
The sources include peer-reviewed data from large-scale cohort studies, including the Nurses’ Health Study II and the Boston Birth Cohort.
The Nurses’ Health Study II cohort evaluated associations between maternal acetaminophen use, during different exposure periods, and ADHD in more than 8800 children born between 1993 and 2005, finding that just over 8% of those children had been diagnosed with ADHD as reported by their mothers (3).
The Boston Birth Cohort study, in approximately 1000 mother-infant dyads, found that cord plasma biomarkers of fetal exposure to acetaminophen were associated with significantly increased risk of childhood autism and ADHD (4).
This is not the first public relations storm the Tylenol brand has had to weather—and it might not even be the biggest.
Almost exactly 43 years ago, in September 1982, seven people in the Chicago area died after ingesting doctored Tylenol capsules that had been laced with cyanide (5). Johnson & Johnson, the makers of Tylenol at the time—the brand was spun off under Kenvue Brands in 2021—was widely lauded for its comprehensive response, which included immediately recalling 31 million bottles and launching a public awareness campaign, in addition to a then-revolutionary decision that has become ubiquitous in the decades since: the introduction of tamper-evident packaging (5,6).
In this case, Kenvue’s response has been just as swift: A visit to the main page of Tylenol’s website on the morning of Sept. 23 prompts a pop-up window with a reassuring message to the public and a link to an FAQ page with more information (7,8).
Tylenol.com homepage screenshot on Sept. 23, 2025. | Image Credit: Patrick Lavery - MJH Life Sciences
“The facts remain unchanged: Over a decade of rigorous research, endorsed by leading medical professionals, confirm[s] there is no credible evidence linking acetaminophen to autism,” the pop-up says (7). “High fevers and pain are widely recognized as potential risks to a pregnancy if left untreated, especially in the first trimester. Remember to talk to your doctor.”
The Tylenol FAQ page reiterates that “credible, independent scientific data continues to show no proven link between taking acetaminophen and autism,” and that “medical and public health organizations agree,” while continuing to advocate for communication between pregnant women and their healthcare professionals (8).
The page then links to statements from the American College of Obstetricians and Gynecologists (ACOG), the Society for Maternal-Fetal Medicine (SMFM), and the Autism Science Foundation, all dated Sept. 5, 2025.
“Pregnant patients should not be frightened away from the many benefits of acetaminophen, which is safe and one of the few options pregnant people have for pain relief,” Christopher Zahn, MD, ACOG chief of clinical practice, was quoted as saying in an ACOG Facebook post (9).
“At this time, the weight of scientific evidence that acetaminophen use during pregnancy causes an increased risk for autism or ADHD is simply inconclusive,” said SMFM President Sindhu K. Srinivas, MD (10). “In maternal-fetal medicine, as in all of medicine, our recommendations are based on an evaluation of rigorous research and data, clinical expertise, and our patients’ values and preferences.”
“It is disingenuous and misleading to boil autism’s causes down to one simple thing,” said Alycia Halladay, PhD, chief science officer at the Autism Science Foundation (11). “We know that autism is incredibly complicated, and we need to move away from studies that simplify it down to one exposure without any other considerations.”
The current dispute highlights the vulnerability of long-established drugs to renewed safety scrutiny. Even when causal evidence is lacking, observational findings can influence policy and public perception, forcing the industry to respond quickly to maintain confidence (1–4).
For manufacturers, the situation underscores the value of clear and rapid communication. Kenvue’s public messaging shows how companies must balance reassurance with openness to further study, particularly when regulatory bodies may revisit labeling or guidance (7,8).
On the research side, the debate may stimulate investment in mechanistic and biomarker studies that go beyond epidemiology. For discovery and development teams, it illustrates the need to anticipate potential safety questions earlier in the pipeline (3,4).
At the manufacturing level, even precautionary warnings could prompt companies to adjust supply strategies, labeling, or risk management plans. The Tylenol case demonstrates that legacy medicines can become focal points for political and scientific debate, demanding ongoing vigilance from the industry (9–11).
1. The White House. Fact: Evidence Suggests Link Between Acetaminophen, Autism. WhiteHouse.gov, Sept. 22, 2025.
2. Bhattacharya, J.; Makary, M.; and Oz, M. Opinion | The Trump Administration’s New Steps to Tackle Autism. Politico.com, Sept. 22, 2025 (accessed Sept. 23, 2025).
3. Liew, Z.; Kioumourtzoglou, M.-A.; Roberts, A. L.; et al. Use of Negative Control Exposure Analysis to Evaluate Confounding: An Example of Acetaminophen Exposure and Attention-Deficit/Hyperactivity Disorder in Nurses’ Health Study II. Am. J. Epidemiol. 2019, 188 (4) 768–775. DOI: 10.1093/aje/kwy288
4. Ji, Y.; Azuine, R. E.; Zhang, Y.; et al. Association of Cord Plasma Biomarkers of In Utero Acetaminophen Exposure With Risk of Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder in Childhood. JAMA Psychiatry 2020, 77 (2) 180–189. DOI: 10.1001/jamapsychiatry.2019.3259
5. Hamel-Nelis, M. The Tylenol Case Study: A Masterclass in Crisis Communications. PRandLattes.com, Aug. 28, 2023 (accessed Sept. 23, 2025).
6. Chapman, M. and Murphy, T. Johnson & Johnson to Split Into Two, Aim for Faster Growth. APnews.com, Nov. 12, 2021 (accessed Sept. 23, 2025).
7. Kenvue Brands. Headache & Pain Relief Products and Medicine | Tylenol. Tylenol.com, accessed Sept. 23, 2025.
8. Kenvue Brands. FAQs About Tylenol Products, Safety & Dosing | Tylenol. Tylenol.com, accessed Sept. 23, 2025.
9. ACOG. American College of Obstetricians and Gynecologists – ACOG’s Post. Facebook.com, Sept. 5, 2025 (accessed Sept. 23, 2025).
10. SMFM. SMFM Statement on Acetaminophen Use During Pregnancy and Autism. SMFM.org, Sept. 5, 2025 (accessed Sept. 23, 2025).
11. Autism Science Foundation. Statement from Autism Science Foundation Regarding Wall Street Journal Report “RFK Jr., HHS to Link Autism to Tylenol Use in Pregnancy and Folate Deficiencies.” AutismScienceFoundation.org, Sept. 5, 2025 (accessed Sept. 23, 2025).
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