Active substance is loratadin (antihistaminic). It has a long half live. As far as I know, there is only one study on it, with women who have taken a single dose of 40 mg ; ratio milk/plasma was 0,6-1,2, and the baby was taking at most 17,4 µg/kg/day of active substance. There is no study on how it passes into breast milk with a long treatment. Long half live gives possibility of accumulation in breast milk. It is used here in pediatric. Posology between 2 to 12 years : 5-10 mg/day. Possible to use another drug. Ceterizin and terfadin are said to be a better choice for a breastfeeding mother. Kindly Françoise Railhet LLL France Medical Associates Program