Individuals can take most DayQuil products every four to six hours as needed or as directed by a doctor, states WebMD. Individuals using DayQuil Cough may take a dose every six to eight hours, according to Vicks.
DayQuil products are formulated to relieve a multitude of symptoms, including sore throat, nasal congestion, cough, fever and headache, states Vicks. DayQuil is available as liquid, caplets or LiquiCaps. Although ingredients vary slightly depending on the exact product used, DayQuil typically combines acetaminophen with a cough suppressant, expectorant and decongestant, according to WebMD. Potential side effects of DayQuil include dizziness, drowsiness, headache, nausea and problems sleeping.