Abstract
A 29-year-old female was admitted to our hospital because of right pleural effusion. Chyle was obtained by thoracocentesis. She received conservative therapy, however, the pleural effusion did not decrease. Thoracic duct ligation was performed, and improvement of the chylothorax was observed. Because there was no underlying disease to cause chylothorax, the diagnosis of idiopathic chylothorax was made. Idiopathic chylothorax is a rare disease and only 24 cases have been reported in Japan.