Harvard Dean's Expert Testimony Deemed 'Unreliable' in Tylenol Lawsuits Following $150,000 Payment

Expert testimony provided by Dr. Andrea Baccarelli, Dean of the Harvard T.H. Chan School of Public Health, was ruled inadmissible by a federal judge in a multi-district litigation concerning alleged links between prenatal Tylenol use and neurodevelopmental disorders. The decision came after Dr. Baccarelli disclosed receiving approximately $150,000 for his work as an expert witness for the plaintiffs, prompting scrutiny over the objectivity of his scientific conclusions. A social media post by user Crémieux highlighted the payment, stating, "> He was paid $150,000," and questioned the consistency and reliability of his published work and testimony.

U.S. District Judge Denise Cote of the Southern District of New York found Dr. Baccarelli's testimony, along with that of four other experts, to be "unreliable," noting that he "downplays those studies that undercut his causation thesis and emphasizes those that align with his thesis." Judge Cote further stated that Dr. Baccarelli had "cherry-picked and misrepresented study results" in his expert report for the lawsuits. This ruling effectively dismissed hundreds of lawsuits filed against Kenvue, the manufacturer of Tylenol, though the plaintiffs are appealing the decision.

Dr. Baccarelli's payment of $150,000 was disclosed during a 2023 deposition, where he estimated spending over 200 hours on the case. This financial arrangement has raised concerns about potential conflicts of interest, especially given the judge's criticisms of his scientific methodology. Notably, in 2022, Dr. Baccarelli co-authored a study that cautioned against changes in clinical practice regarding acetaminophen use, a position that seemingly contradicted his expert testimony in the litigation.

More recently, a 2025 scientific review co-authored by Dr. Baccarelli, which found an "association" but not a "causal relationship" between prenatal acetaminophen use and neurodevelopmental disorders, was cited by Trump administration officials, including Robert F. Kennedy Jr. and Marty Makary, as evidence of a causal link. Other researchers have criticized the review's methodology, suggesting it was biased and included unadjusted findings to strengthen the reported association. The 2025 review itself acknowledged Dr. Baccarelli's expert witness role as a potential conflict of interest.

The case underscores the critical importance of transparency and impartiality for expert witnesses in legal proceedings and academic researchers. The allegations against Dr. Baccarelli highlight the ongoing debate regarding the ethical implications of financial incentives in scientific and legal contexts, particularly when influencing public health messaging and court outcomes.