Respiratory infections are the most common type of infection encountered in both clinical and daily life, primarily divided into upper and lower respiratory tract infections. An upper respiratory tract infection, commonly referred to as a cold, is mainly characterized by nasal congestion, runny nose, and sore throat, and is mostly caused by viral infections. In the early stages, antiviral medication can be taken, and by checking a complete blood count, one can preliminarily determine whether the infection is viral or bacterial, deciding whether antibiotics are needed for treatment. Lower respiratory tract infections, on the other hand, are often caused by conditions such as pneumonia or bronchitis, which are mostly bacterial infections requiring targeted antibiotic treatment. For patients who are physically weaker, immunocompromised, or elderly and frail, there may also be a possibility of fungal co-infection, necessitating the use of antifungal medications for treatment.