The weak cough suppressant effect of Ambroxol is determined by the pharmacological action of Ambroxol. Ambroxol is an expectorant drug, not a cough suppressant, and its mechanism of action is to reduce the viscosity of sputum by breaking down the polysaccharide fibrous component of glycoproteins in sputum, which causes degradation and breakage of the fibrous component. It also increases the secretory activity of the bronchial glands, resulting in increased secretion in the bronchi. It can promote the oscillatory function of bronchial cilia, which facilitates the expulsion of sputum, and thus acts as a phlegm dissolver. Ambroxol can also stimulate the secretory activity of type II alveolar epithelial cells and increase the secretion of surface active substances, which is conducive to the repair of bronchial and alveolar epithelium and reduces the stimulation of cough receptors, and has a certain cough suppressant effect. Since the cough suppressing mechanism of Ambroxol does not directly act on the cough reflex, but only reduces the stimulation, the cough suppressing effect is very weak, and it mainly acts as an expectorant.