Original formula NyQuil liquid cold and flu medicine contains 25 percent alcohol by volume, according to the State University of New York Potsdam. The percentage of alcohol is not listed on the label. Alcohol is the second inactive ingredient listed on the 12-ounce NyQuil Cold & Flu Nighttime Relief label.
NyQuil delivers a dose of alcohol along with acetaminophen to relieve fever and dextromethorphan to suppress cough. Antihistamine doxylamine succinate offers temporary relief of cold symptoms and can be sedating.
When Proctor & Gamble introduced Vicks NyQuil in 1968, the dark green liquid was touted as “The Nighttime, Sniffling, Sneezing, Coughing, Aching, Stuffy Head, Fever, So-You-Can-Rest Medicine.”