No information is available on the use of venetoclax during breastfeeding. Because venetoclax is more than 99% bound to plasma proteins, the amount in milk is likely to be low. However, its half-life is 26 hours and it might accumulate in the infant. Most sources consider breastfeeding to be contraindicated during maternal antineoplastic drug therapy.[1] The manufacturer recommends that breastfeeding be discontinued during vemurafenib therapy and for 1 week after the final dose. Chemotherapy may adversely affect the normal microbiome and chemical makeup of breastmilk.[2] Women who receive chemotherapy during pregnancy are more likely to have difficulty nursing their infant.[3]