In the clinical sputum examination when there is no sputum, you can spit out the sputum through the way, such as through the back row, from the bottom to the top of the back patting repeated several times, you can also take the body position is the head is lower than the higher position to discharge. Then you can choose bronchial fiberoptic endoscopy, endoscopy through the fiber-optic guide sputum suction out of the airway to obtain a sputum specimen. Clinical sputum examination is mainly through the collection of secretions in the airway, through the general characterization, including microscopic examination, pathogen examination for the diagnosis and differential diagnosis of respiratory diseases. Through these ways, sputum can be obtained to achieve the purpose of sputum examination to confirm the diagnosis of the cause of the disease.