Pulmonary cavities are often seen in the following diseases: 1. lung abscess, which can be combined with cough, coughing sputum, chills, fever and other symptoms, high blood count, anti-inflammatory treatment is effective. 2. tuberculosis can also lead to pulmonary cavities and can have multiple cavities, even cavities with liquid flat, can also be combined with cough, coughing sputum, fever and other symptoms, sputum can be positive for antacid bacilli, PPD test can also be positive, anti-TB treatment is effective. 3. 3, lung tumor, lung tumor can appear cavity, cavity inner wall hairy, irregular, eccentric cavity is common. If the cavity is found in the chest CT, bronchoscopy, sputum for tuberculosis, sputum for cancer cells, and blood tests should be performed to further clarify the cause.