Healthy people rarely have sputum, sputum volume is low in acute respiratory inflammation, increased sputum volume is common in bronchiectasis, lung abscess and bronchopleural fistula, and sputum expectoration is related to body position, sputum volume can be layered phenomenon after resting, the upper layer of foam, the middle layer of plasma or plasma-purulent, and the lower layer of necrotic material. Foul-smelling sputum suggests anaerobic infection. Rust-colored sputum is typical of pneumococcal pneumonia. Its clinical examination is as follows. 1, X-ray examination: in the early stage, only the thickening of lung texture or the involvement of lung segments and lobes are slightly blurred. As the disease progresses, the alveoli are filled with inflammatory exudates, showing a large shadow of inflammatory infiltrate or solid shadow, bronchial insufflation can be seen in the solid shadow, and there can be a small amount of pleural effusion at the angle of the rib diaphragm; in the dissipation period, the X-ray shows that the inflammatory infiltrate is gradually absorbed, and there can be a piece of area absorbed more quickly, presenting the sign of “pseudo-cavity”, and the disease will not completely dissipate until 3 to 4 weeks later. In most cases, it takes 3-4 weeks for the disease to completely dissipate. In most cases, it takes 3 to 4 weeks for the disease to completely dissipate. Elderly patients have slower dissipation of the lesions, and they are prone to incomplete absorption and become organic pneumonia. Laboratory examination: blood leukocyte count (10～20)×109∕L, neutrophils more than 80%, with nuclear left shift, intracellular toxic particles can be seen. The white blood cell count may not be increased in the old and weak, alcoholism, immunocompromised people, but the percentage of neutrophils is still high. Sputum direct smear for Gram stain and pod stain microscopy, if found typical positive Gram stain, with pods of diplococci or streptococci, can make a preliminary diagnosis of the pathogen. Sputum culture can determine the pathogen in 24-48 hours. Polymerase chain reaction and fluorescent labeling antibody detection can improve the rate of pathogenic diagnosis. Coughing up rust-colored sputum is an acute inflammatory condition involving most or all of the lobes of the lungs, mainly caused by Streptococcus pneumoniae, with diffuse intra-alveolar fibrinous exudation. In addition to pneumococci, L. pneumophila, Staphylococcus aureus, Streptococcus hemolyticus, and Haemophilus influenzae can also cause lobar pneumonia.