The active ingredients in benylin dry coughs original help to suppress the urge to cough dry coughs are caused by an inflammation of the airways which can be caused by dust foreign bodies or an infectionampnbspbenylin dry cough original containsampbull dextromethorphan helps to suppress coughingampbull diphenhydramine hydrochloride helps relieve a runny nose and ampbull levomenthol helps to ease congestion and help you breathe more easilyeven after your cold or flu has gone sometimes a coug