Most of the unanswered questions about breast milk arise from the drugs that the mother has to use when she becomes ill. Drug use affects the biochemical content and therefore energy of breast milk, but the problem is not so simple. Mainly important for the newborn during breast feeding; it is the right choice of drugs that the mother has to use. The pathways of drug excretion to breastmilk and their effects on the baby in short and long periods of time are problematic despite the fact that the researchers have directed the researchers to various studies. The American Academy of Pediatrics has removed some medicines from contraindicated list in 2001. Instead, these drugs are categorized as agents that need to be used with caution. Therefore, contraindications should be evaluated on a patient basis with benefits and risks for both mother and baby. The presence of adverse effects reported in the literature or theoretical risks of adverse effects does not mean contraindication, but a careful approach may be necessary (eg monitoring the baby for physical / behavioral changes).