The US FDA withdrew emergency-use authorization of bamlanivimab and etesevimab in June of 2021 because of a lack of efficacy against COVID-19 variants. Bamlanivimab is a monoclonal antibody given together with etesevimab. Both are directed against the SARS-CoV-2 virus that causes COVID-19. No information is available on the clinical use of bamlanivimab during breastfeeding. Because bamlanivimab is a large protein molecule with a molecular weight of 146,000 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] Until more data become available, bamlanivimab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant.