Sahih Bukhari
Beginning of Creation
Volume: 004 / Book Number: 054 / Hadith Number: 483
Narrated Abu Jamra Ad-Dabi:
I used to sit with Ibn 'Abbas in Mecca. Once I had a fever and he said (to me), "Cool your fever with Zam-zam water, for Allah's Apostle said: 'It, (the Fever) is from the heat of the (Hell) Fire; so, cool it with water (or Zam-zam water)."