There are many drugs used to treat coughs, and they can generally be divided into two broad categories: first, phlegmolytic drugs. Phlegmolytics are used to dilute the phlegm so that it can be more easily expelled from the body. Cough suppressants inhibit or block the cough reflex by acting on various parts of the cough, thus stopping the cough. Therefore, simple dry cough can be treated with phlegm-suppressing drugs, such as tranylcypromine hydrochloride or acetylcysteine, or bromhexine. Second, cough suppressants. Cough suppressants are also used, including codeine, dextromethorphan, pentoxifylline, and levomepromazine. However, in addition to symptomatic treatment for cough, it is most important to identify the cause of the cough and treat it for that cause. Therefore, if a dry cough at night interferes with rest and sleep, appropriate cough suppressant treatment can be administered, otherwise it is best to clarify the cause before administering relative treatment.