Powerful Cough Relief for Day or Night. NyQuil Cough gives you nighttime cough relief so you can sleep. Then let DayQuil Cough--the daytime, non-drowsy, cough relief--take on your cough while you tackle your to-do list.; DayQuil Cough temporarily relieves cough due to minor throat and bronchial irritation. Non-Drowsy.; NyQuil Cough temporarily relieves cold symptoms including cough, runny nose and sneezing so you can sleep.; When using DayQuil or NyQuil products, carefully read each label to insure correct dosing. Use as directed. Keep out of reach of children.