The Prophet (ﷺ) said, "Fever is from the heat of Hell, so abate fever with water."
Sahih al-Bukhari Book 76, Hadith 40
← Previous Hadith Whenever a lady suffering from fever was brought to Asma' bint Abu Bakr, she used to invoke Allah for her and then sprinkle some water on her body, at the chest and say, "Allah's Messenger (ﷺ) used to order us to abate fever with water."

Sahih al-Bukhari Book 76, Hadith 39 Next Hadith → I heard Allah's Messenger (ﷺ) saying, "Fever is from the heat of Hell, so abate fever with water."

Sahih al-Bukhari Book 76, Hadith 41