The severity of pneumonia cannot be generalized and can be mild or severe. In the case of common pneumonia, the patient is young and has no underlying disease, and the pneumonia can recover quickly with systematic treatment. If the patient is an elderly person with underlying disease or severe pneumonia, it will be more serious. Common manifestations of common pneumonia include coughing, coughing up sputum, sometimes with pus sputum or blood sputum, and accompanied by shortness of breath, dyspnea and other symptoms. Common pneumonia can recover quickly after systematic treatment, especially in young people with few underlying diseases. If the patient develops impaired consciousness, depression, coma, convulsions, or unstable and low blood pressure, it suggests severe pneumonia. This situation suggests that the condition is more serious and may be life-threatening; especially for the elderly, patients with long-term lung disease, or patients with heart disease, diabetes and other diseases, pneumonia in this case is still more critical, and there is a possibility of life-threatening. Pneumonia is recommended to receive regular treatment as soon as possible. Normally, we should pay attention to keep warm, moderate exercise, quit smoking, etc., in order to strengthen the resistance and prevent the occurrence of pneumonia.