Tonsillectomy is the most common surgery in children. Post-tonsillectomy pain is universal and associated with considerable morbidity. Dipyrone is banned in some countries and the analgesic most commonly used in others. Evidence of the effectiveness of dipyrone in postoperative analgesia of tonsillectomy are scarce. Serious adverse effects such as agranulocytosis and anaphylaxis are rare and their incidence varies in different populations.