The difference between coughing with and without phlegm is mainly the amount of inflammatory secretions in the airways. Generally, coughing with cold is mainly caused by the infection of viruses, bacteria and other pathogens, which causes inflammatory reactions in the mucous membrane of the upper respiratory tract. In contrast, a large amount of inflammatory secretions will result in coughing and sputum, which is a wet cough with sputum, and blood tests can usually be performed clinically to clarify the condition and cause. For a dry cough only, cough suppressants are given, and for a cough with phlegm, a combination of phlegm-removing drugs can be used.