title: Background of mucolytic treatments in chronic bronchitis.
mesh_terms: D001991:Bronchitis / Q000188:drug therapy*; D002908:Chronic Disease; D005100:Expectorants / Q000627:therapeutic use*; D006801:Humans; D009093:Mucus / Q000187:drug effects / Q000502:physiology
chemical_list: D005100:Expectorants