I used to sit with Ibn `Abbas in Mecca. Once I had a fever and he said (to me), "Cool your fever with Zamzam water, for Allah's Messenger (ﷺ) said: 'It, (the Fever) is from the heat of the (Hell) Fire; so, cool it with water (or Zamzam water).
Sahih al-Bukhari Book 59, Hadith 71
← Previous Hadith Allah's Messenger (ﷺ) said, "The (Hell) Fire complained to its Lord saying, 'O my Lord! My different parts eat up each other.' So, He allowed it to take two breaths, one in the winter and the other in summer, and this is the reason for the severe heat and the bitter cold you find (in weather).

Sahih al-Bukhari Book 59, Hadith 70 Next Hadith → I heard the Prophet (ﷺ) saying, "Fever is from the heat of the (Hell) Fire; so cool it with water."

Sahih al-Bukhari Book 59, Hadith 72