The authors determined the concentrations of some antiepileptic drugs (carbamazepine and valproic acid) in the serum of mother and in mother's milk with subsequent advisory activity concerning breast feeding. Until now the authors examined the levels of carbamazepine in mother's milk of 14 mothers (women who have just given birth) and the levels of valproic acid in 20 such subjects. The mean level of carbamazepine in the serum of mother of our group was 5.578 μg/ml and that of the milk was 1.174 μg/ml. The ration of the level of carbamazepine in the milk and serum of the mothers was on the average179, maximum ratio being 0.5 and the minimum ratio 0.03. None of the ratios of the levels of carbamazepine in the plasma and milk was in the range of contraindication for breast feeding. None of the suckling children was found to suffer from untoward effects of the therapy with carbamazepine. The mean value of valoproic acid in the serum of mothers in this group was 57.715 μg/ml, the value in the mother's milk being 2.896 μg/ml. None of the breast feeding mothers had a higher level of valproic acid that the maximum therapeutic level, the levels were mostly in the area of lower therapeutic levels. None of the children whose mothers was taking valproic acid in the course of breastfeeding suffered from side effects of the therapy. More than the 15% of admitted level of valproic acid the mother's milk from the serum level of valproic acid was observed in two breastfeeding mothers and they were recommended to stop the breastfeeding.

        Key words: antiepileptic drugs (carbamazepine, valproic acid), breast feeding