If conservative treatment is not effective, surgical treatment should be considered 8 . Studies indicate that ligation of the thoracic duct and pleurodesis are efficient alternatives for resolution of chylothorax 9 .Recently, thoracic duct ligation through video-assisted thoracic surgery has been used in patients who did not respond to conservative treatment. Kirby et al 11 describe this conduct as less painful and with fewer postoperative complications.Pereira et al 12 describe the use of lymphatic ligation for the treatment of postoperative chylopericardium. However, in our country, ligation of the thoracic duct for the treatment of postoperative chylothorax is still a rare procedure, and at what point the conservative treatment should be replaced by postsurgical treatment is still controversial. Thus, our study evaluates the initial results of ligation of the thoracic tract in 4 patients with chylothorax unresponsive to conservative treatment. Case ReportsCase 1 -A four-year-old-male patient with congenital cardiopathy and cyanosis at birth with a previous history of pulmonary atresia without interventricular communication, single left ventricle, hypoplastic right ventricle with sinusoids, left pulmonary artery stenosis, and coronary artery cavitary fistulas. At 5 days of life, he underwent atrial septotomy with the Rashkind procedure, and after 2 days, he underwent a modified left Blalock Taussig shunt procedure. At 4 years old, he underwent a bidirectional Glenn operation with maintenance of the previous Blalock shunt, evolving, in the postoperative period with low cardiac output maintained with vasoactive drugs. He was discharged on the 5th postoperative day, when minor pleural effusion was suspected. A chest X-ray was indicated.After chylothorax was diagnosed, pleural drainage was started. Parenteral nutrition and fasting were introduced after 1 week. The patient evolved with significant persistence of pleural drainage. Nineteen days after the initial In children, chylothorax occurs mainly after cardiac and thoracic surgeries. One of the recommended postsurgery treatments is ligation of the thoracic tract, when all other conservative treatments have failed. We report 4 cases of chylothorax in patients who were successfully treated with this approach, which resulted in a decrease in pleural drainage without recurrent chylothorax.Chylothorax refers to the presence of lymphatic fluid in one or both pleural spaces, secondary to leakage in the thoracic duct or one of its main tributaries 1 . Quinke 2 first described traumatic chylothorax in 1875, after rupture of the thoracic duct.When chylothorax is not treated, the risk of death is high, with rates above 45% 3 , requiring, in the majority of the cases, aggressive treatment.According to DeMeester 4 , chylothorax may be according to its cause, either congenital, traumatic, neoplastic, or multiple causes. Among the traumatic causes surgical procedures with a thoracic approach may cause thoracic duct lesions, leading to the development of chylothorax. Postoperat...