Cold & Flu Treatment Over the Counter What You Need to Know About NyQuil By Kristina Herndon, RN Updated on February 17, 2023 Medically reviewed by David Snyder, PharmD Print NyQuil is a very popular medication used to treat cold and flu symptoms. Find out if it is right for you and your symptoms. Antonio_Diaz / Getty Images Active Ingredients (in each 15ml tablespoon) Acetaminophen 500mg (pain reliever) Dextromethorphan HBr 15mg (cough suppressant) Doxylamine succinate 6.25mg (antihistamine) Dosage Adults - Two tablespoons every six hours as needed for cold and flu symptoms. Do not take more than four doses in 24 hours.Children - Ask a healthcare provider. Uses for Nyquil Temporary relief of cold and flu symptoms including: CoughSore ThroatHeadacheMinor aches and painsFeverRunny noseSneezing Side Effects of Nyquil DrowsinessExcitability, especially in children Warnings Do not consume if you drink more than three alcoholic drinks a day. Acetaminophen can cause liver damage. Ask your healthcare provider if you should take acetaminophen if you regularly drink more than three alcoholic drinks per day.Do not use with other medications containing acetaminophen.Do not use this medication if you are taking an MAOI (medication for depression, psychiatric, emotional conditions or Parkinson's disease) or for two weeks after stopping an MAOI. Ask a Healthcare Provider Before Use If you have glaucoma If you have a cough that produces a lot of mucus If you have a breathing problem or chronic cough that is caused by asthma, smoking, chronic bronchitis or emphysema If you have trouble urinating because of an enlarged prostate If you are taking sedatives or tranquilizers If you are pregnant or breastfeeding Caution Stop use and ask a healthcare provider if: Pain or cough worsens or lasts more than seven days Fever worsens or lasts more than three days Redness or swelling is present in area causing pain New symptoms occur Cough returns or occurs with a rash or headache that won't go away Other NyQuil Information Do not take this product when you have to operate machinery, drive a vehicle or perform other tasks that require alertness. Nyquil is likely to make you very drowsy; be sure you can devote time to sleep before taking this product. Frequently Asked Questions Why does NyQuil make me sleepy? Ingredients in Nyquil that control cough and congestion have side effects that cause you to feel sleepy. Dextromethorphan, a cough suppressant in Nyquil, and doxylamine succinate, an antihistamine, cause drowsiness. Learn More Over-the-Counter Sleep Aids How often can I take NyQuil? You can take two NyQuil LiquiCaps every six hours or 30 ml of NyQuil Liquid every six hours. Do not take more than four doses of NyQuil in a 24-hour period. Learn More Which Cold Medicine Can You Take with High Blood Pressure? Can I take NyQuil for COVID? Cold medications such as NyQuil may help relieve some symptoms of COVID such as coughing or sore throat, but they will not cure you of the illness. If you're taking any other medications, check with your doctor first since there may be some interactions. Also, do not take any additional acetaminophen (including Tylenol) while using NyQuil. Learn More Guide to COVID-19 4 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. U.S. National Library of Medicine. Label. Vicks Nyquil Cold and Flu - acetaminophen, dextromethorphan hydobromide, and doxylamine succinate capsule, liquid filled. DailyMed. Vicks. Vicks Nyquil FAQ. U.S. Food & Drug Administration. Acetaminophen: avoiding liver injury. Memorial Sloan Kettering Cancer Center. Managing COVID-19 at Home. By Kristina Herndon, RN Kristina Herndon, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention. See Our Editorial Process Meet Our Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit