The diagnosis of cancer complicates 0,02–0,1% of all pregnancies, posing a real predicament for the future mother, her family and the team of physicians. Usually it is advised to stop breastfeeding during systemic therapy. Nevertheless the emerging data evaluate recommendations about safety of lactation during chemotherapy. The benefits of breastfeeding encourage to look closely at this issue. We present the current data on the use and safety chemotherapeutic agents during lactation.