The Book on Salutations and Greetings (Kitab As-Salam)
Muslim :: Book 26 : Hadith 5482
Asma' reported that a woman running high fever was brought to her. She asked water to be brought and then sprinkled it in the opening of a shirt at the uppermost part of the chest and said that Allah's Messenger (may peace be upon him) had said: Cool (the fever) with water. for it is because of the vehemence of the beat of Hell.