When a cold is not good for half a month, this is the time to consider the presence of pathological factors, such as more serious pathogenic infections, the presence of purulent bacteria, Staphylococcus aureus, Mycobacterium tuberculosis, fungi and other infections. It is also seen in the presence of complications, such as acute bronchitis, acute pneumonia, lung abscess, or even bronchopleural fistula, pus pneumothorax, etc. Blood tests, CT of both lungs, and culture of respiratory secretions for pathogens can be taken to clarify the cause of the disease and provide active symptomatic and anti-causal treatment. For fungus, drugs such as amphotericin B can be used; for tuberculosis, early, combined, long-term and regular treatment with anti-tuberculosis drugs; for bacteria, drugs such as amoxicillin, cefoperazone or azithromycin can be chosen.