The purpose of thoracentesis is twofold: one is to clarify the diagnosis; and the other is the treatment of the disease. For example, thoracentesis and aspiration of pleural effusion is performed to clarify what causes the disease. Routine examination of pleural fluid, biochemical examination and bacterial culture of pleural fluid plus drug sensitivity test are performed to clarify whether the pleural fluid is caused by tuberculosis, infection, or tumor. For example, after having pneumothorax or pleural effusion, puncture and suction are performed to reduce the pressure of fluid and air on the lungs and heart, and to reduce the symptoms of chest tightness and shortness of breath.