From A Service of the U.S. National Library of Medicine and the National Institute of Health http://www.nlm.nih.gov/medlineplus/ency/article/003090.htm
A lukewarm bath or sponge bath may help cool someone with a fever. This is especially effective after medication is given -- otherwise the temperature might bounce right back up.
DO NOT use cold baths or alcohol rubs. These cool the skin, but often make the situation worse by causing shivering, which raises the core body temperature.