New Study Challenges Long-Held Concerns Over Infant Ibuprofen and Acetaminophen Use

A major study challenges earlier concerns about common infant painkillers, revealing reassuring early findings.

A major clinical trial is offering reassurance to parents about two of the most commonly used medications in infancy.

Researchers report that paracetamol (also known as acetaminophen, e.g., Tylenol, Panadol) and ibuprofen (e.g., Advil, Nurofen), widely given for fever and pain, show no link to eczema or bronchiolitis during a baby’s first year.

Concerns about these drugs have lingered for years. Earlier observational studies hinted that paracetamol use in infancy might increase the risk of asthma, eczema, and other immune-related conditions later in childhood.

“Our study found that paracetamol and ibuprofen are incredibly safe to use in young children,” says lead researcher Professor Stuart Dalziel, Cure Kids Chair of Child Health Research at Waipapa Taumata Rau, University of Auckland, and Pediatrician at Starship Children’s Hospital.

“These results give parents and health professionals high confidence to continue to use these important medications.”

Large-Scale Study Design

The trial followed nearly 4,000 babies in New Zealand from birth. Participants were randomly assigned so that parents used either paracetamol or ibuprofen when treating fever or pain during the first year of life.

Researchers regularly surveyed parents about symptoms of eczema, asthma, and bronchiolitis. They also reviewed prescription records and hospital data to ensure accurate reporting.

Findings from the first year have been analyzed and published in The Lancet Child & Adolescent Health.

Eczema developed in about 16 percent of infants who received paracetamol and 15 percent of those given ibuprofen. Bronchiolitis affected about 5 percent of babies in both groups. These differences were not statistically significant.

Serious adverse effects were rare, and none were linked to the medications. Overall, the study found no association between either drug and eczema or bronchiolitis, confirming their safety in early life.

This is the first randomized controlled trial, considered the gold standard in research, to directly examine this question.

Ongoing Research and Long-Term Goals

The research is part of a broader project called the ‘Paracetamol and Ibuprofen in the Primary Prevention of Asthma in Tamariki (PIPPA Tamariki) study’.

This is the largest pediatric trial ever conducted in New Zealand, with participants being followed from birth through age six.

Additional findings are expected when the children reach ages three and six.

Investigating Future Health Outcomes

The long-term aim is to determine whether paracetamol use in infancy is linked to conditions that can only be reliably diagnosed later in childhood.

“We know that two-thirds of children who are wheezy at age three years don’t develop asthma by age six,” says Dalziel.

“Thus, we need to wait until school age to ultimately test if paracetamol in the first year of life causes asthma.”

Researchers are also examining developmental conditions such as autism and attention-deficit hyperactivity disorder (ADHD), which are typically diagnosed at older ages.

Lead author Dr. Eunicia Tan, a senior lecturer at the University of Auckland and emergency physician at Middlemore Hospital, says, “Ultimately, the study will provide important evidence regarding the link between paracetamol use and asthma, eczema, hay fever, and developmental disorders, such as autism and ADHD.”

Reference: “Paracetamol versus ibuprofen as required for fever or pain in the first year of life and the risk of eczema and bronchiolitis at age 1 year in New Zealand (PIPPA Tamariki): a multicentre, open-label, parallel-group, superiority, randomised controlled trial” by Eunicia Tan, Christopher J D McKinlay, Judith Riley, Medhawani Rao, Lisa Mravicich, Shirley Lawrence, Allie Eathorne, Irene Braithwaite, Alex Semprini, Karaponi Okesene-Gafa, Nicolette Sheridan, Karen Hoare, Cameron Grant, David Johnson, Mark Weatherall, Richard Beasley and Stuart R Dalziel, 27 January 2026, The Lancet Child & Adolescent Health.
DOI: 10.1016/S2352-4642(25)00341-4

The study was funded by the Health Research Council of New Zealand and Cure Kids and run by the University of Auckland and the Medical Research Institute of New Zealand, Wellington.

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