No information is available on the use of bezlotoxumab during breastfeeding. Because bezlotoxumab is a large protein molecule with a molecular weight of about 148,200 Da, the amount in milk is likely to be very low.[1] It is also likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal.[2] Waiting for at least 2 weeks postpartum to resume therapy may minimize transfer to the infant.[3] If bezlotoxumab is required by the mother, it is not a reason to discontinue breastfeeding. Until more data become available, bezlotoxumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant.