There are several reasons why coughing often occurs when you have a cold: First, the most common factor is infection around the trachea and bronchus when you have a cold, and coughing occurs after the infection, because the infection of the respiratory tract leads to high reactivity of the airway, and coughing and coughing up sputum occurs at this time, and the self-protection mechanism in the airway is activated. Secondly, it is a reaction of the nature of phlegm discharge, such as the appearance of purulent and inflammatory secretions in the respiratory tract, the cilia of the respiratory tract will accelerate the oscillation, and the process of oscillation will produce coughing, which is a reflex and reaction of the body’s self to expel the virus and bacteria of the cold from the respiratory tract. If the cold is not controlled in time or if the medication is not correct, the cough may worsen.