Lawsuit Alleges Enfamil, Similac Cow’s Milk-Based Formula Caused Infant’s NEC Diagnosis

Federal trials over NEC diagnoses from cow’s milk-based infant formulas are scheduled to begin this summer.

A Louisiana mother has filed a product liability lawsuit alleging that cow’s milk-based infant products sold under the Similac and Enfamil brand names caused her premature child to develop a life-threatening gastrointestinal disease.

The complaint (PDF) was brought by Merissa Mahan, individually and on behalf of Minor Child W.D., in the U.S. District Court for the Northern District of Illinois on June 3. It names Abbott Laboratories Inc., Abbott Laboratories, Mead Johnson & Company LLC and Mead Johnson Nutrition Company as defendants.

Mahan claims the manufacturers knew for years that premature infants fed cow’s milk-based formulas and fortifiers face a significantly increased risk of necrotizing enterocolitis (NEC) compared to infants receiving an exclusive human milk diet, yet continued to aggressively market the products as safe and beneficial.

Cow’s Milk-Based Formula NEC Risks

Necrotizing enterocolitis is a severe gastrointestinal condition that primarily affects premature and low birth weight infants. The disease causes inflammation and destruction of intestinal tissue, which can lead to bowel perforation, life-threatening infections, the need for emergency surgery and death.

Over the last several years, a growing number of Similac lawsuits and Enfamil lawsuits have been filed against Abbott and Mead Johnson, alleging that the manufacturers failed to warn hospitals and parents that premature infants fed cow’s milk-based formulas and fortifiers face a substantially increased risk of developing NEC.

Across much of the infant formula litigation, plaintiffs claim that cow’s milk based products have been aggressively marketed as safe and beneficial for premature babies despite decades of scientific research linking these products to a higher incidence of NEC, when compared to an exclusive human milk diet.

Enfamil, Similac NEC Allegations

According to the lawsuit, W.D. was born prematurely at Lake Charles Memorial Hospital for Women in Louisiana in November 2017 and was fed cow’s milk-based infant formula while receiving treatment in the neonatal intensive care unit. The complaint alleges the infant developed NEC shortly after receiving the products, resulting in catastrophic injuries.

The filing accuses Abbott and Mead Johnson of marketing Similac and Enfamil as safe, medically endorsed nutrition options for premature infants, while failing to disclose research allegedly linking cow’s milk-based formula to an increased risk of NEC. The companies also allegedly promoted the products to parents and healthcare providers by emphasizing growth and development benefits for premature babies.

Mahan further alleges the manufacturers failed to provide adequate warnings on product labels, failed to recommend that parents be informed of NEC risks before the products were used in NICUs and continued selling the formulas despite the availability of safer human milk-based alternatives.

“As a direct and proximate result of the inadequacy of the warnings and the pervasive marketing campaigns suggesting the safety and necessity of their products, W.D. was fed cow’s milk-based products, which caused W.D. to develop NEC.”

— Merissa Mahan v. Abbott Laboratories Inc. et al.

The lawsuit presents claims of design defect, failure to warn, negligence, intentional misrepresentation, negligent misrepresentation, breach of express and implied warranties and violation of the Louisiana Products Liability Act. Mahan seeks compensatory damages for past, present and future emotional distress, loss of enjoyment of life, pain and suffering, mental anguish, loss of consortium and other non-economic losses.

Infant Formula NEC Lawsuits

Due to the growing number of NEC infant formula lawsuits filed by families nationwide, all federal claims have been centralized since April 2022 in a multidistrict litigation, or MDL, before U.S. District Judge Rebecca R. Pallmeyer in the Northern District of Illinois. The consolidation is designed to avoid duplicative discovery, inconsistent pretrial rulings and unnecessary delays, since the lawsuits raise similar allegations involving cow’s milk-based formulas and fortifiers sold by Abbott and Mead Johnson.

The litigation now includes hundreds of claims brought by families who allege the manufacturers failed to adequately warn that products like Similac and Enfamil may increase the risk of NEC when given to premature infants. While each lawsuit involves a different child and set of injuries, the cases share common questions about what the companies knew, what warnings were provided to hospitals and parents, and whether safer human milk-based alternatives should have been recommended.

As part of the coordinated proceedings, Judge Pallmeyer has scheduled a series of early bellwether trials to help the parties evaluate how juries may respond to evidence that will likely be repeated throughout the litigation. The first federal bellwether trial is scheduled to begin on July 6, involving claims brought by Alexis Inman. A second bellwether trial is scheduled for August 10, involving a lawsuit filed by Mary Kelton of California.

The outcomes of these early trials will not be binding on other families pursuing NEC lawsuits. However, they will be closely watched by both sides, since the verdicts may help shape future settlement negotiations and determine whether Abbott and Mead Johnson continue defending claims individually or move toward a broader resolution of the litigation.

Infant Formula NEC Verdicts

In addition to the federal litigation, a series of infant formula NEC lawsuits involving Similac products have also been filed in state courts, with several having already gone to trial.

In one of the earliest trials, a Missouri jury awarded nearly $500 million to a family in the summer of 2024. Later that year, a second Missouri case initially resulted in a defense verdict, but the trial judge overturned that outcome after finding that Abbott Laboratories introduced improper evidence and ordered a new trial. More recently, an Illinois state court jury in Cook County awarded four mothers a combined $70 million in damages.

In a separate case involving the Enfamil formula, another Cook County jury returned a $60 million verdict in 2024.

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