We previously performed thoracentesis to diagnose pseudochylothorax in five patients and performed underwater chest tube drainage. Pleural biopsy was performed in one patient who was admitted with no primary disease resulting from pseudochylothorax. Mean initial drainage was 1,100 mL/s. All patients recovered with conservative treatment, except one in whom pulmonary expansion could not be achieved, so that thoracotomy and decortication were necessary. These procedures were difficult and incomplete because of severe inflammation and thickening of the pleura. Multiple incisions were made over the pleura to expand the lobes.