TO THE EDITORDesloratidine (Clarinex, Neoclarytin, Aerius, Azomyr, Opulis,Allex), the principal active metabolite of loratadine is itself a new oral antihistamine drug Its main indications are for the treatment of seasonal allergic rhinitis (SAR) and chronic idiopathic urticaria (CIU). The pharmacologic profile of desloratidine offers particular benefits, in terms of histamine H1-receptor binding potency and H1 selectivity. It has a half-life of 21-27 h, permitting a once-daily dose. No specific precautions are required with respect to its administration in renal or hepatic failure. No clinically relevant racial or gender variations in the disposition of desloratidine have been noted.We present here a clinical case of acute reversible idiosyncratic liver toxicity, related to its administration.