Inhibitor of Epidermal Growth Factor receptor that acts by inhibition of tyrosine kinase phosphorylation and used for treatment of several types of cancer. At latest update, relevant published data on excretion into breast milk were not found. Because of high serum protein-binding capacity, excretion into breast milk in significant amount is seemingly unlikely. If continuation of safely breastfeeding is desired without assuming high risk for potentially severe side-effects, elimination of total burden of drug should be kept. For this to happen, breastfeeding should be stopped for 10 half-lives (T ½). It means wait 15 days after the last dose before resuming breastfeeding. Meanwhile, frequent pump-and-dump is recommended for maintenance of milk production.