When People Got Sick: Infant Botulism Outbreak, November 2025

Key points

CDC, public health officials in several states, the California Department of Public Health Infant Botulism Treatment and Prevention Program, and the U.S. Food and Drug Administration, are investigating a multistate outbreak of infant botulism linked to infant formula. Infant botulism happens when a baby swallows Clostridium botulinum spores that grow in the gut and make toxin. Infant botulism often starts with constipation but is usually first noticed as difficulty feeding (sucking and swallowing), a weak and altered cry, and lack of head control.

Can of ByHeart infant formula

When people got sick

This chart shows when 39 infants in this infant botulism outbreak got sick.