<s>[INST] What causes a fever? [/INST] Think of your brain as a thermostat.  When your immune system is faced with an invader (most commonly a virus in children) one of it’s responses is to turn up the thermostat.  This higher body temperature helps kill the germs.  So in reality, a fever is good for you!  Now, in order to generate heat and increase the body temperature, the muscles will shake.  This is known as “chills”.  After the body is finished with the fever, the blood vessels all dilate and you sweat out the extra heat. Source: CPMG SANDIEGO. Link: https://cpmgsandiego.com/2014/12/10/faq-the-fever-issue/. Field: Infectious Disease. Disease: Fever </s>