A significant outbreak of infant botulism linked to ByHeart baby formula has resulted in the hospitalization of 51 infants across 19 states. The Food and Drug Administration (FDA) confirmed on December 10, 2023, that these cases involve infants who consumed the affected formula. This marks an increase from 39 cases reported earlier this month.
Botulism is a serious and rare illness that can lead to paralysis and death. According to the FDA, the cases reported span a period from August 1, 2025, onward, but a recent update has expanded the investigation to include 10 additional cases occurring between December 2023 and July 2025. All affected infants have been hospitalized, but no fatalities have been documented thus far.
The outbreak has affected infants in various states, including Arizona, California, Illinois, and Ohio, among others. Ohio was the latest state added to the list, which now encompasses a total of 19 states. The illnesses began between August 9 and November 19, 2023.
The FDA has not received reports of any recalled formula being available for sale since November 26, 2025. In its statement, the FDA emphasized that all products under the ByHeart brand have been recalled, including all formula cans and single-serve “anywhere pack” sticks.
Concerns arose earlier this month when some consumers reported spotting ByHeart products still on store shelves at major retailers such as Walmart, Target, and Kroger, despite the ongoing recall. ByHeart previously held about 1% of the U.S. infant formula market, selling approximately 200,000 cans each month.
Ongoing testing by ByHeart, the FDA, the Centers for Disease Control and Prevention (CDC), and state officials is currently underway, with results anticipated within the coming weeks. Parents and caregivers are advised to stop using the affected formula and dispose of any remaining product.
The FDA has identified specific lots of the ByHeart Whole Nutrition Infant Formula that were recalled. All infants affected by the outbreak have received treatment, primarily through a medication known as BabyBIG, which is derived from pooled blood plasma of adults immunized against botulism. This treatment is the only effective solution for infant botulism and is available through California’s Infant Botulism Treatment and Prevention Program.
Dr. Erica Pan, California’s state health officer, highlighted that testing confirmed the presence of the botulism-causing bacteria in a sample from a can of ByHeart formula that was fed to an infant who later fell ill. The testing process involves injecting mice with the cultured bacterium to observe if they become ill, a method that has yielded quick results in this case.
Officials have yet to identify any other brands of infant formula or sources contributing to the outbreak. ByHeart has issued statements regarding its response, emphasizing their commitment to consumer safety and the swift actions taken to address potential risks. The company stated, “From the very beginning, we have acted quickly and decisively to remove any potential risk.”
Infant botulism is typically reported in fewer than 200 cases annually in the United States. The condition arises from a bacterium that produces a toxin in the intestines. Infants are particularly susceptible as their immune systems are not fully developed, allowing the spores to thrive and produce harmful toxins.
Symptoms of botulism in infants can take weeks to manifest and include poor feeding, loss of head control, and breathing difficulties. Experts believe that despite the seriousness of this outbreak, there is minimal risk of widespread infant formula shortages, given ByHeart’s small market share compared to larger companies.
In summary, the FDA and CDC continue to monitor the situation closely, and further updates are expected as investigations proceed. Parents are reminded to remain vigilant and discard any recalled ByHeart products to ensure the safety of their infants.
