On January 19, 2023, Plaintiff Tamie Maddox filed her Complaint against Defendant Conopco, Inc. d/b/a Unilever Home & Personal Care USA, alleging that Defendant, a New York corporation with its principal place of business located at 700 Sylvan Avenue, Englewood Cliffs, New Jersey 07632, caused Plaintiff to suffer from hair loss after she used Defendant’s TRESemmé shampoo containing DMDM hydantoin (“DMDM”).
Plaintiff alleged that the DMDM preservative used in Defendant’s products including the TRESemmé Keratin Smooth Shampoo is a chemical that releases a carcinogen known as formaldehyde, which has long been associated with causing hair loss, thinning hair, dermatitis, and other adverse scalp reactions, and has been the subject of numerous complaints and various lawsuits.
According to Plaintiff’s medical expert, dermatologist Dr. Marc J. Serota, “Defendant’s product caused her hair loss due to an allergic reaction to DMDM.” However, Defendant filed a motion to preclude Serota from testifying at trial.
Dermatology Expert Witness
Dr. Marc Jonathan Serota is triple board-certified in dermatology, pediatrics, and allergy and immunology. Serota is recognized as a national expert in dermatology and allergy topics. He also frequently lectures across the country and has published numerous articles in his areas of expertise.
Discussion by the Court
To begin with, Defendant argued that Serota formed his opinion without conducting procedures normally performed by dermatologists outside the litigation context. Moreover, Defendant asserted that Serota’s theory in this case lacked scientific support and that he failed to establish that DMDM or other chemicals could have caused the alleged hair loss at the levels of concentration these chemicals are found in Defendant’s products. Defendant noted that Plaintiff has not consulted with a doctor in several years, that she has been uninsured since 1996, and that she has never been tested for an allergy to DMDM.
Serota testified that he essentially relied entirely on Plaintiff’s self-report of her symptoms and some photographs of the affected areas on her body to come to his opinion.
In this case, because Plaintiff effectively lacked any significant medical records or other medical history that could have informed Serota’s opinion as to her specific condition, Serota would have had to perform some physical examination or laboratory tests to credibly determine whether Plaintiff does in fact have an allergy to DMDM.
He did not do that here, and as a result, the Court cannot credit his testimony and allow him to present his opinions to a jury as those of a properly informed expert.
Held
The Court granted Defendant’s Daubert motion to preclude Marc Serota from testifying at trial.
Key Takeaway
A physician who evaluates a patient in preparation for litigation should seek more than a patient’s self-report of symptoms or illness. Therefore, the physician should either examine the patient or review the patient’s medical records.
Case Details:
| Case Caption: | Maddox V. Conopco, Inc. |
| Docket Number: | 2:23cv293 |
| Court Name: | United States District Court for the District of New Jersey |
| Order Date: | May 12, 2026 |
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