Acute bronchitis may lead to lung infections if not treated in time, but the specific evolution time is related to the individual patient’s constitution and treatment, and cannot be generalized. Acute bronchitis is a self-limiting disease, mainly due to inflammatory changes in the tracheo-bronchial mucosa. In mild cases, especially in young and strong people, the symptoms of cough and sputum can be relieved within 5-7 days by paying attention to the regulation of living habits, drinking more water and taking rest. However, in elderly and frail patients with underlying diseases such as chronic bronchitis, COPD, emphysema, bronchial asthma or children, acute bronchitis may progress to pneumonia and even cause a series of serious complications, resulting in a longer duration of illness. Therefore, it is recommended to go to the respiratory medicine department of a regular hospital in time to have a rationalized treatment plan formulated by a professional doctor when symptoms appear.