Lungs can be washed, but it should be noted that lung washing generally refers to lavage of the alveoli rather than flushing of the lung tissue. Alveolar lavage refers to the injection of lavage fluid into the bronchi and fine bronchioles through fiberoptic bronchoscopy or electronic bronchoscopy, reaching all the way to the alveoli, and then suctioning, repeated several times, to serve the purpose of lavage of the alveoli. Alveolar lavage can have the effect of removing some of the pathogenic bacteria, secretions and necrotic tissues in the bronchial tubes, and is clinically the preferred method of treating pulmonary protein deposition. In addition, alveolar lavage can be used clinically to diagnose some diseases, such as asthma, pulmonary nodular disease, bronchiectasis, lung tumors and so on. If Mycobacterium tuberculosis is found in the alveolar lavage fluid, tuberculosis can be diagnosed; if detached cancer cells are found, lung malignant tumors can be diagnosed. Therefore, alveolar lavage has certain diagnostic and therapeutic value in the clinic, and needs to be carried out under the guidance of specialized physicians.