Ambroxol is a bronchial expectorant that also exhibits antioxidative activity. Ambroxol stimulates the ciliary beat frequency and increases mucous secretion in the lung and trachea. In clinical settings, ambroxol increases levels of thioredoxin and thioredoxin reductase, decreasing oxidative stress and suppressing acute exacerbation of chronic obstructive pulmonary disorder (COPD). In monocytes, ambroxol inhibits LPS-induced proliferation of PDGF and prevents activation of ERK. Additionally, this compound inhibits sodium nitroprusside-induced activation of guanylate cyclase in an NO-dependent manner.