Expectorant is used to thin mucus, which makes it easier to cough while decongestants are used to provide upper respiratory congestion from common illnesses, such as colds and flu. Cough expectorants are typically used to treat chest congestion that derives from illnesses, such as bronchitis and pneumonia. They are not effective for dry, hacking coughs, which are often produced from the common cold.
In addition to cough expectorants, other cough medicines include suppressants and topical salves, which are applied to the chest and throat to alleviate symptoms of chest tightness. While cough expectorants are used to make coughs more productive, cough suppressants are ideal for treating dry and hacking coughs. While cough syrups are used to treat symptoms associated specifically with coughs, decongestants are used to alleviate conditions in the head, throat or chest. Decongestants and expectorants vary in their ideal use as well as in their chemical composition. Most decongestants contain narcotics, which helps people to sleep, and may also contain aromatic ingredients and vapors. The most common ingredient in cough expectorants is called guaifenesin, which helps to clear viscous mucous that forms on the surfaces of airways. Both medications may interact with other types of medicines, and are available as over-the-counter remedies or prescribed by physicians.