To help determine which drugs can be used with relative safety during pregnancy, we reviewed the literature on the possible teratogenic, perinatal, behavioral or developmental effects of the various groups of commonly used psychiatric drugs, and their effects on lactation. Tricyclic antidepressants, fluoxetine, phenothiazines, and most benzodiazepines are not considered to be teratogenic and may be used during pregnancy. All anti-epileptic drugs seem to have an embryotoxic and teratogenic potential and we recommend, if possible, avoiding these drugs. Lithium administration during the first trimester of pregnancy increases the risk of cardiac malformations, but the risk is not as high as originally reported. Therefore lithium may be continued whenever it seems to be the "drug of choice" if fetal echocardiography and ultrasonography are performed. There is a lack of information on the teratogenic effect of the newer drugs, and in spite of the fact that similar "older" drugs do not seem to adversely affect the fetus, they should be used with care. Although the data on the development of children following in-utero exposure to psychiatric drugs is limited, there seems to be no evidence of any long-term adverse effects on the development of children exposed to most psychotropic medications. However, children exposed in utero to anti-epileptic drugs may exhibit long-term developmental problems. Most of the drugs are detected in breast milk only at low concentrations. In nursing women taking these drugs, breastfeeding is possible. The infant should be carefully monitored for any clinical side effects and whenever observed, nursing should be discontinued. In light of our knowledge today, there seems to be only rarely an indication for pregnancy interruption following maternal exposure to psychiatric drugs during pregnancy.