TYLENOL: The Pain Reliever Class Action Lawsuits Need to Target Most
New scientific study links acetaminophen exposure with autism “without any reasonable doubt”
In 1996, Stephen Schultz’s son was sick for three weeks. The boy had a rash on his stomach and suffered from diarrhea and extreme irritability. The illness developed just after a measles, mumps, and rubella vaccine and the doctor office told the parents to give their son acetaminophen.
After what Schultz describes as his son’s “slow slide” into autism, Schultz closed the doors on his established dentistry practice and embarked on a journey to find out what happened to his child.
In the following years, he earned his Ph.D. at the University of California and, in 2008, published a peer-reviewed scientific paper with a team of other researchers that uncovered a shocking 8-fold increase in autism in children who took acetaminophen—known in the U.S. as Tylenol—following an adverse reaction to vaccines compared to children who had adverse reactions to vaccines but did not take the drug.
Schultz’s 2008 paper provided incisive evidence that acetaminophen was one of the leading causes of autism in babies and young children.
However, because most children taking acetaminophen appear to be fine, and because the medical industry incorrectly assumed the drug to be safe for use in babies and children, this groundbreaking research was tragically ignored.
Autism is considered a spectrum disorder. Some children are so acutely affected by it that they are unable to speak or toilet themselves and will need 24-hour care for their entire lives. People with autism are at high risk of premature death. In fact, one study found that the average life expectancy for a person with autism is 36 years old.
The numbers of people affected by autism continue to rise. In the 1970s and early 1980s autism was so rare that most medical doctors had never seen a single case.
It was thought, back then, to affect some 3.1 in 10,000, according to Dr. Darold Treffert, who published the first “Epidemiology of Infantile Autism” in the Archives of General Psychiatry in 1970.
Today, according to new research by a team of Chinese scientists published in JAMA Pediatrics, 1 in 30 children is suffering from autism.

My colleague, Dr. William Parker, like Stephen Schultz, had an established career that changed dramatically when he began investigating the connection between acetaminophen and autism.
As a scientist at Duke University for more than 27 years, Parker led the team that discovered that the human appendix functions as a safe-house for beneficial bacteria. In February 2021, Parker was the first to predict that people in lower income countries would be protected from COVID-19 because of the biodiversity in their bodies, a theory that has turned out to be correct.
A tremendously prolific scientist, Parker published a 2021 study in PLOS One that shows that acetaminophen leads to developmental changes in baby lab animals, resulting in long-term increases in non-social behavior.
In that study, Parker’s lab used doses of acetaminophen in lab animals that, when adjusted for weight, were actually less than doses currently approved for use in infants and toddlers.
As Parker pointed out to me, “Our finding shows that acetaminophen could never be approved for pediatric use by today’s regulatory standards.”
The Nail in the Coffin for Pediatric Tylenol
Parker’s latest peer-reviewed study, published last week in a prestigious Italian pediatric journal, should be the nail in the coffin for pediatric acetaminophen use.
In that 40-page paper, Parker points toward no fewer than 17 compelling lines of evidence that lead his team to conclude that acetaminophen, “without any reasonable doubt” is a contributing factor for many—if not most—cases of autism.
Parker and colleagues, including scientists at Duke University and the University of North Carolina, explain that, although most babies and children are not affected by the drug as far as we know, there exist certain factors that put babies and children at risk.
These factors include genetic predisposition, concomitant infections, repeated antibiotic use, environmental toxic exposures, and even some seemingly innocuous symptoms of more serious undiagnosed conditions that few would suspect.
For example, as Parker points out, if your child cannot keep food down for just two consecutive meals, the scientific literature demonstrates that the risk of acetaminophen toxicity for your child may be double that of a child not experiencing digestive disruption.
While the interplay between inadvertent forced fasting via regurgitation and increased acetaminophen toxicity risk is well established in the scientific literature using laboratory animal models (see here and here, for instance), many pediatricians are generally unaware of the dangerous connection between the two.
In addition, circumcised boys have an almost 50 percent greater incidence of autism than uncircumcised boys, a fact that may be causally understood if acetaminophen use during the procedure causes autism.
Parker’s 17 lines of evidence are impressive, and are summarized in the 4th table of the review. Understandably, Parker considers this evidence insurmountable.
“Any competent law-enforcement agency would have resolved this issue a decade ago,” he insists. “In my experience, with very rare exceptions, parents who are aware of the available evidence will avoid giving acetaminophen to their babies and children.”
Parker’s study addresses several additional issues, including why, incredibly, modern medicine has not recognized this terrible tragedy.
Indeed, a reasonable person might assume that, if the world’s most common over-the-counter children’s drug causes a dramatic increase in autism, then somebody would have already put a halt to the catastrophe.
However, as Parker points out, autism is often attributed to the reason for giving the drug, and autism is often not diagnosed until long after the drug is given. In a nutshell, it’s impossible to see a big picture with a scientific microscope.
Without Any Reasonable Doubt
Parker and colleagues describe a modern medical system designed to detect encroaching dangers, not dangers already existing within the system. An astounding mathematical proof is provided, with results shown in Tables II and III of their manuscript, showing that the current standards of data analysis in the medical industry cannot detect hazards imposed by something as commonplace as acetaminophen, even when it profoundly injures 1 percent of all children.
This new evidence pointing “without any reasonable doubt,” to the hazards of acetaminophen for brain development in babies and children does not stand alone.
Earlier this year, Parker’s team published a peer-reviewed formal proof in another prestigious pediatric journal that demonstrated that acetaminophen was never shown to be safe for babies and children in the first place.
Tylenol Alternatives
Given all of this, parents are left with a seemingly difficult choice. How should we treat pain and fevers in our children?
The good news is that this dangerous drug is not necessary. There are many natural remedies and safer alternatives for everything from teething pain to fevers, as I explain in this 2017 article, “Tylenol Alternatives: Better Safer Remedies.”
It's also important for parents to understand that the vast majority of fevers are not dangerous and may be beneficial. Letting the fever burn while helping your child be more comfortable should be a parent’s primary objective while caring for a sick child.
William Parker left Duke University and now runs a non-profit research lab. Both he and Dr. Stephen Schultz abandoned established careers for something more important: ending the autism epidemic.
Tylenol should be taken off the market for pediatric use. At the very least, given the growing body of scientific evidence that shows it is not safe for developing brains, there should be black warnings on every bottle.
Until then, parents must be savvy about Tylenol. It’s not safe. It doesn’t belong on your cabinet shelf or in your baby’s body. The safest place for baby Tylenol is in the trash.
Related Articles:
Tylenol Lawsuits
Tylenol: Better, Safer Remedies
Tylenol During Pregnancy
Awesome work Jennifer. What follows is speculation that life expectancy dropped may also be due to causes ignored by science.
It continues to astound me that long term biology and evolution are ignored in modern medicine. The dictum "First Do No Harm" seems to be dropped by the way side with our natural vibrant history going back 3.5 billion years.
We should be looking at what we have changed in the biosphere that has changed health and longevity. Sorry I do go on. One last thing. Before the Industrial revolution there were centenarians on both sides of my family. After the advent of the Industrial revolution (after the US civil war) life expectancy dropped by 30 years. My great grandma who was 3 years old when Custer made his last stand lived to be 103. She was the last centenarian on my dad's side. Likewise my mom's great grandma also live to me more than 100. None on her side since have lived to be that old. Why?
Excellent information. Thank you for sharing. I've shared this with several friends and family.