Closed chest drainage plays an important role in maintaining negative pressure in the pleural cavity and draining fluid and air from the pleural cavity. Because the drainage tube for closed chest drainage may need to be left in place for several days, ten days or even a month, it may be necessary to change the drainage bottle and the fluid in the bottle during this period. Regarding closed chest drains done after cardiac surgery, after sterile thoracic surgery, and after trauma surgery, the fluid in the drainage bottle needs to be routinely changed daily, but there is no specific time regarding the change of the drainage bottle. In general, for closed drainage of pneumothorax, aseptic pleural effusion, post-operative aseptic surgery, etc., in addition to changing the fluid in the bottle once a day, the water seal bottle can be changed once every 5-7 days. If the patient is abscess chest or tuberculous abscess chest, the chest infection is more serious, in addition to daily replacement of the fluid in the chest drainage bottle, the drainage bottle should not be changed more than once a week, generally 3-5 days can be replaced.