How does an ice pack help to bring fever down?

An Ice pack relives inflammation by cooling down blood vessels. The coolness helps calm down the inflammation and takes the pain away. It also numbs it. The rapid cooling numbs the inflamed area, thus making it less painful. In medical terms: The cold causes vasoconstriction changing the blood flow to the area. The blood flow is reduced and hence the swelling goes down. Improved by Pegalita, medical administrator.