This is an antihistamine. There are approximately 2 billion antihistamines on the market. There is not a lot of information about this one. It is probably safe, but if we are not sure, why stop breastfeeding? Why not use something else. Or why not assume that it is safe and keep an eye on the baby. Weaning a 13 month old by force is likely to harm the baby a lot more than a small amount of antihistamine, which, by the way is probably being prescribed for a lot of babies with allergies. Jack Newman, MD, FRCPC