If your nose gets used to them, nasal congestion may return when you stop using the decongestant, even after your cold has passed. If you do nothing, the rebound congestion will pass after a while. Cough suppressants may provide relief if you have a dry hacking cough that interferes with sleep or work. Expectorants An expectorant may be included in a cold medication to loosen the mucus in the lungs, making it easier to clear the lungs when you cough. There is some disagreement about whether expectorants work.
Some cold medications contain both an expectorant and a cough suppressant.
This combination is somewhat self-defeating since one ingredient is trying to make a productive cough while the other is trying to stop it all together. Many liquid cold preparations contain alcohol because many medications dissolve well in it. Alcohol also acts as a sleep inducer and may add to the sedative effect of an antihistamine. Check the label carefully if you cannot tolerate alcohol. For a child, avoid alcohol medications entirely, or choose one with as little alcohol as possible.