Cold and bronchitis are two relatively common clinical diseases, the two have obvious differences, as follows: 1. Pathogenesis: cold belongs to the acute upper respiratory tract infection, while bronchitis belongs to the lower respiratory tract infection. The majority of colds are caused by viral infections and are therefore self-limiting, with a course of about a week, while bronchitis is an acute inflammation of the bronchial mucosa and surrounding tissues, which can be caused by viral infections, bacterial infections, and physical and chemical factors. The typical symptoms of bronchitis are cough, phlegm, or fever. Bronchitis caused by viral infection is self-limiting, while bronchitis caused by bacterial infection needs to be treated with antibiotics, such as amoxicillin and cephalexin.