Levocetirizine is the R-enantiomer of cetirizine. Based on limited information from cetirizine and levocetirizine, levocetirizine appears to be acceptable during breastfeeding.[1,2] Larger doses or more prolonged use may cause drowsiness and other effects in the infant or decrease the milk supply, particularly in combination with a sympathomimetic such as pseudoephedrine or before lactation is well established. International guidelines recommend cetirizine, the racemic form of the drug, as an acceptable choice if an antihistamine is required during breastfeeding.[3,4]