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A fever is a temporary increase in body temperature, often due to an illness. Having a fever is a sign that something out of the ordinary is going on in your body.

You have a fever when your body temperature rises above its normal range. The average normal temperature is 98.6 F (37 C). However, body temperature can vary by a degree or more — from about 97 F (36.1 C) to 99 F (37.2 C) — and still be considered normal.

Fevers generally go away within a few days. Over-the-counter medications can treat a fever, but sometimes it’s better left untreated. Fever plays a key role in helping your body fight off infection.
Sometimes the cause of a fever can’t be identified. Often, a fever is related to the following:

  • A viral or bacterial infection
  • Heat exhaustion or extreme sunburn
  • Heavy exercise
  • Your menstrual cycle
  • Certain inflammatory conditions, such as rheumatoid arthritis
  • Some medications, such as antibiotics and high blood pressure and seizure medications
  • Some immunizations

When to see a doctor

A high fever is a greater cause for concern in infants and children than in adults. It’s generally recommended you see a doctor if your child is:

  • Younger than age 3 months and has a rectal temperature of 100.4 F (38 C) or higher.
  • Ages 3 to 6 months and has a temperature up to 102 F (38.9 C) and seems unusually irritable, lethargic or uncomfortable or has a temperature higher than 102 F (38.9 C).
  • Ages 6 to 24 months and has a temperature higher than 102 F (38.9 C) that lasts longer than a day but shows no other symptoms. If your child has other signs and symptoms, such as a cough or diarrhea, you might call your child’s doctor sooner.
  • A newborn and has a lower than normal temperature — less than 97 F (36.1 C). Very young babies may not regulate body temperature well when they’re ill and may become cold rather than hot.

In older children, contact a doctor if you child has a fever of 102 F (38.9 C) or higher that lasts longer than three days or is accompanied by other symptoms, including severe headache; stomachache; throat swelling; skin rash; unusual irritability; listlessness; confusion or vomiting.

It’s generally recommended that adults contact a doctor if they have a temperature of 103 F (39.4 C) or higher, a fever that lasts for longer than three days, or a fever that’s accompanied by other symptoms that are worrisome.


  • Drink plenty of fluids. Fever can cause fluid loss and dehydration, so drink water, juice, or broth. For a child younger than age 1, use an oral rehydration solution such as Pedialyte. These solutions contain water and salts proportioned to replenish fluids and electrolytes.
  • Rest. You need rest to recover, and activity can raise your body temperature.
  • Stay cool. Dress in light clothing, keep the room temperature cool, and sleep with only a sheet or light blanket.


In the case of a high fever, your doctor may recommend an over-the-counter medication.


You may be able to prevent fevers by taking these steps to reduce your exposure to infectious diseases:

  • Wash your hands often. Washing hands is especially important before eating, after using the toilet and after being around someone who’s sick. Teach your children to do the same.
  • Try to avoid touching your nose, mouth or eyes. These are the main ways that viruses and bacteria can enter your body.
  • Cover up. Cover your mouth when you cough and your nose when you sneeze. Teach your children to do the same.
  • Avoid sharing. This applies to cups, water bottles, and utensils.

 Excerpt From: The Mayo Clinic. “Mayo Clinic A to Z Health Guide”.

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