The frequency of postnatal mental disorders requiring psychopharmacological treatment raises the question whether breast feeding can be recommended in some cases. This paper summarizes recent information regarding benefits and risks of breast feeding for infants of psychopharmacologically treated mothers. If a mother insists upon breast feeding, a careful risk-benefit-consideration has to take place. New results indicate that the advantages of breast feeding can outweight the given risks of maternal pharmacotherapy, if minimal necessary drug-doses of an agent with a small amount of passage into milk are prescribed. Monitoring of the serum-levels is advisable especially during the first three months. The nursing infant has to be closely controlled for any adverse effects.