What causes a fever?

A fever has many causes and can be a symptom of almost any illness. Among the most common are:

However, if you or a loved one are experiencing a higher-than-normal body temperature and no other symptoms of illness, do not assume something is wrong. A person's body temperature changes throughout the day and varies with many normal activities and emotions. For example, stress, excitement, wearing extra clothing, food, certain medications, a woman's menstrual cycle and exercise can all raise body temperature. Also, children tend to have a slightly higher body temperature than adults.

Last reviewed by a Cleveland Clinic medical professional on 01/23/2019.


  • Hague R. Managing the child with a fever. Practitioner. 2015;259(1784):17-21, 2-3.
  • Tess AV. Chapter 8. Fever. In: Henderson MC, Tierney LM, Jr., Smetana GW. eds. The Patient History: An Evidence-Based Approach to Differential Diagnosis. New York, NY: McGraw-Hill; 2012. library.ccf.org
  • NHS Choices. Fever in children. Accessed 2/27/2019.

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