Because pneumonia includes lung infections, it is impossible to simply compare which is more serious, lung infection or pneumonia. Lung infections are caused by abnormal infectious lesions that occur when lung tissue is invaded by pathogens such as bacteria, viruses, and mycoplasma, whereas pneumonia may develop as a result of physical or chemical stimuli or other non-infectious factors in addition to pathogen invasion. Both lung infections and pneumonia are potentially completely curable, but can be life-threatening if not treated properly or in a timely manner. Each patient’s condition is different, and the treatment used will vary, making a difference in the prognosis the patient receives. The severity of pneumonia depends mainly on the oxygenation status, such as the presence of severe hypoxemia, the underlying disease status, such as the combination of chronic lung disease, heart disease, etc., as well as the status of the autoimmunity, such as the presence of leukemia and AIDS. However, whether it is a lung infection caused by a pathogen or a pneumonia with a more varied etiology, early and regular diagnosis and treatment is essential.