Clinical use of cough and phlegm drugs are many, according to the actual situation of the selection of targeted drugs for treatment, commonly used cough and expectorant drugs are expectorants, cough suppressants, such as bromhexine hydrochloride, Pentoxyverine, codeine and so on. 1. Expectorants (1) Nauseating expectorants: weak effect, commonly used ammonium chloride. (2) Stimulating expectorants: mainly volatile substances, including eucalyptus oil. (3) Mucous phlegm dissolvers: common drugs include bromhexine hydrochloride, which can reduce the viscosity of phlegm, making it easier to cough. In addition, bromhexine hydrochloride can also enhance the swinging ability of the cilia on the mucous membrane of the respiratory tract and promote phlegm expulsion. It can be used in the treatment of various types of bronchitis, bronchial dilatation, phlegm viscous not coughing phlegm caused by emphysema and other symptoms. 2.Cough suppressants (1) Central cough suppressants: directly inhibit the cough center, cough effect is rapid and powerful, common drugs are Pentoxyverine, codeine, dextromethorphan and so on. (2) peripheral cough suppressants: mainly through the inhibition of the cough reflex arc in any pathway to achieve the effect of cough, including phenprocoumon, Narcotics. Before using cough and phlegm medication, you must be guided by a professional doctor, do not use medication arbitrarily, and in the process of using medication, you should pay attention to avoiding strenuous exercise, eating light and easy-to-digest food, and actively replenishing water to speed up the recovery.