Fever
Educational information. Individual clinical review of this presentation by Dr. Ehsan is not yet documented. It does not replace personal medical evaluation.
Source: MedlinePlus, National Library of Medicine. Read the original source
MedlinePlus data edition September 26, 2026. Imported September 27, 2026. These dates do not indicate a new clinical review of the article.
A fever is a body temperature that is higher than normal. A normal temperature can vary from person to person, but it is usually around 98.6 °F (37 °C). A fever is not a disease. It is usually a sign that your body is trying to fight an illness or infection.
Infections cause most fevers. You get a fever because your body is trying to kill the virus or bacteria that caused the infection. Most of those bacteria and viruses do well when your body is at your normal temperature. But if you have a fever, it is harder for them to survive. Fever also activates your body's immune system.
Other causes of fevers include:
- Medicines, including some antibiotics, blood pressure medicines, and anti-seizure medicines
- Heat illness
- Cancers
- Autoimmune diseases
- Some childhood vaccines
Treatment depends on the cause of your fever. If the fever is very high, your health care provider may recommend taking an over-the-counter medicine such as acetaminophen or ibuprofen. Adults can also take aspirin, but children with fevers should not take aspirin. It is also important to drink enough liquids, to prevent dehydration.
Symptoms, tests and care options
Further reading selected by MedlinePlus. Links open the original organizations’ websites.
- Fever · American Academy of Family Physicians
- Fever in Infants and Children · American Academy of Family Physicians
- Fever: First Aid · Mayo Foundation for Medical Education and Research
- Thermometers: Understand the Options · Mayo Foundation for Medical Education and Research
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For a life-threatening emergency, call 911 in the U.S. or your local emergency number.
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