The FDA has issued a warning about the potential dangers of probiotics for preterm infants, citing more than two dozen adverse events linked to the products since 2018. The agency is investigating whether probiotics have contributed to other cases in babies and has sent a letter to health care providers about the dangers of these products. Parents and caregivers are urged to talk to their health care provider before giving probiotics to preterm infants and to report any adverse events to the FDA's MedWatch Adverse Event Reporting program.