The approximate number of days needed to drain pleural effusion varies from person to person. If the condition is mild and the effusion is small, it is usually drained for 3-5 days; if the effusion is large, it may need to be drained for 7-9 days, and if the effusion is malignant and accompanied by respiratory difficulties, it may need to be drained for a long time. Drainage of pleural effusion is mostly considered to mean closed chest drainage. At present, the time of drainage of pleural effusion needs to be based on the actual condition, which cannot be generalized and there is obvious individual variability. Usually, the indication for removing the chest drain is that the amount of pleural drainage fluid is less than 50-100 ml per day and more than 3 days. For patients with mild condition and less pleural effusion, it takes about 3-5 days to drain the pleural effusion; however, for patients with large amount of pleural effusion, the time for draining the pleural effusion will be prolonged, and it may take 7-9 days; for malignant effusion, it is necessary to consider the time for drainage according to the patient’s condition and the presence of respiratory distress. Clinical indications for closed chest drainage include pneumothorax, hemothorax, pyothorax, etc., which has a certain auxiliary therapeutic effect on the treatment of the disease. Patients need to strengthen the care of the drainage tube, avoid pressure on the drainage tube, and maintain patency and tightness. To summarize, patients who are draining pleural effusion need to actively cooperate with the doctor’s treatment, and report to the doctor in time if any discomfort occurs.