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. But remember, a cough that produces mucus can be useful in clearing your breathing passages, so not all coughs should be suppressed. 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. Other ingredients 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.