ByHeart Formula Botulism Litigation Consolidated as MDL-3178

The first infant botulism outbreak linked to commercial baby formula is now a federal multidistrict litigation. In May 2026, the Judicial Panel on Multidistrict Litigation centralized lawsuits against ByHeart, Inc. into MDL-3178 in the Southern District of New York before Judge Arun Subramanian, starting with roughly 20 actions, according to MDL Update's May 2026 docket report. The consolidation follows an outbreak that sickened 48 infants across 19 states, all of whom required hospitalization, as the Centers for Disease Control and Prevention reported.

The litigation has progressed rapidly. ByHeart recalled all of its Whole Nutrition infant formula on November 11, 2025, and federal investigators expanded the case definition back to December 2023, covering most of the company's production history, NPR reported. For plaintiff firms, an MDL formed this early in a contamination event requires intake screening anchored directly in medical evidence.

What Triggered the Outbreak

Infant botulism is rare. The CDC typically sees 150 to 180 individual cases nationwide each year, making a multi-state outbreak unusual, the agency noted in a December 2025 statement. The signal first surfaced on November 7, 2025, when California's Infant Botulism Treatment and Prevention Program (IBTPP) flagged an increase in sick infants who had consumed ByHeart formula.

Within a day, the CDC and FDA advised parents to stop using specific lots. On November 11, ByHeart recalled all products after Clostridium botulinum was identified in the formula, the CDC's investigation page states. ByHeart represents an estimated 1% of US formula sales, yet accounted for more than 40% of formula-exposed sick infants in the outbreak, according to the FDA.

From Recall to MDL in Six Months

The transition from public health alert to centralized litigation proceeded on an expedited schedule:

This kind of bounded, defined-injury docket fits the criteria the JPML typically looks for when centralizing product-liability claims, as Lawsuit Intelligencer's 2026 mass tort analysis noted. A single product, a single defendant, and a specific diagnosis make ByHeart a clear candidate for coordinated pretrial proceedings.

Why This Is a Records-Intensive Docket

Infant injury cases involve extensive documentation, and ByHeart cases require coordinated retrieval across multiple clinical settings:

• Pediatric and NICU/PICU records documenting the botulism diagnosis and inpatient course
• Emergency department notes capturing the initial presentation before botulism was diagnosed
• BabyBIG treatment records, administered through California's IBTPP, establishing standard-of-care intervention
• Feeding logs and pharmacy or retail purchase records linking the infant to specific ByHeart lots
• Pediatrician well-visit histories establishing baseline health

Because the outbreak window stretches back to 2023, many cases involve records held by multiple hospitals and clinics across different states. LlamaLab retrieves records in 4 days on average (with roughly 30-40% returned same-day on electronic requests) and uses insurance data to fill in treatment gaps clients don't always remember, surfacing facilities, dates, and clinicians as needed. Invoices are itemized per case to flow through as recoverable case disbursements on settlement statements.

Next Steps for Law Firms

With MDL-3178 established, initial proceedings will focus on leadership appointments, census forms, and Plaintiff Fact Sheet protocols.

Summary

MDL-3178 centers on medical evidence. The medical record is the core of each claim, from the BabyBIG treatment records confirming diagnosis to retail proof establishing exposure to recalled lots.

Firms managing intake on this docket should prioritize complete pediatric and hospital records early to verify claim validity.

This article is for informational purposes only and does not constitute legal or medical advice. Sources: MDL Update, CDC Investigation, CDC Newsroom, FDA, NPR, Lawsuit Intelligencer.