The staging of pneumonia, a question that focuses on the pathological staging, is generally divided into four periods: first, the congestive edema period, which is mainly the 1-2 days after the onset of the disease, when the patient can develop fever and chills, and the chest X-ray can show patchy, faint shadows. The second period, red hepatomegaly, is usually the 3rd-4th day after the onset of the disease, when the patient’s disease progressively worsens and he may have chest pain or cough rust-colored sputum. The third period, gray hepatomegaly, is the 5th-6th day after the onset of the disease, when the patient’s lung lobes are enlarged, so the rust-colored sputum coughing up will gradually change into mucus-purulent sputum. The fourth period, the dissolution and dissipation period, generally refers to the period about 1 week after the onset of the disease, when the patient’s body defense function is significantly enhanced and the pathogenic bacteria have been eliminated, and the chest X-ray examination can return to normal at this time, and this period can last for 1-3 weeks.