IE 10 or 11 may display this page improperly. Please upgrade to Microsoft Edge, Google Chrome, or Firefox.

What is a fever?

Ever notice how when you have a fever you feel hot and sweaty? That’s because a fever is a temporary increase in your body temperature, usually the result of an illness or virus. A fever is generally considered to be a temperature reading above 37°C (98.6°F). A fever is your body’s way of telling you that something out of the ordinary is going on inside you. You may experience a high fever or a low grade or mild fever. The good news is that a fever seems to play a key role in helping your body fight off infections. Read on to learn more about what causes a fever and how to treat it.


What causes a fever?

A fever is usually the result of an illness caused by a virus or a bacterial infection, such as when you have a cold or flu, which are both caused by viruses.

How long does a fever last?

In general, a fever can last a few hours or a few days, depending on whether it is associated with a cold or the flu. To help lower a fever, you should drink plenty of fluids, get plenty of rest, and try to stay cool by placing a cool, damp washcloth on your forehead or the back of your neck.

What does a fever feel like?

Wondering how to tell if you have a fever? Since a fever causes a rise in your body temperature, it may make you feel hot and sweaty. Another way to tell if you have a fever is if you feel chilled and find yourself shivering to generate more body heat. You may also experience sweating, a headache and muscle aches when you have a fever.


How can I treat a fever associated with cold or flu?

If you have a fever, it’s a good idea to take an over-the-counter medication containing a fever reducer to help lower your temperature. If you have multiple symptoms associated with your fever, such as a sore throat pain, cough, stuffy nose, headache, or minor aches and pains, you can try taking DayQuil Cold & Flu or DayQuil COMPLETE Cold & Flu which also relieves chest congestion, during the day. At night, reach for NyQuil Cold & Flu or NyQuil COMPLETE Cold & Flu. Both can calm your cough, relieve your runny nose and fever so you can get the rest you need. NyQuil COMPLETE Cold & Flu also relieves nasal congestion. DayQuil and NyQuil contain acetaminophen, which will help decrease your fever fast.

However, you should consult your doctor if you are experiencing any of the below.

  • If your temperature reaches 38°C (100.4°F) or higher.

  • If you’ve had a fever for more than three days.

  • If your fever is accompanied by a severe headache, severe throat swelling, an unusual skin rash, mental confusion, persistent vomiting, or any other out-of-the ordinary symptoms.

View sources



by product

      by symptom

        help & support

        • Contact Us
        • For ingredients and more, Select a product