Mukhtasar Muslim (Abridged) 1468 — Fever is from Hell’s heat; cool it

Narrated from Sayyida Asma' (may Allah be pleased with her) that when a woman suffering from fever was brought to her, she would ask for water and pour it into her collar, and would say that the Messenger of Allah (peace and blessings be upon him) said: "Cool it (the fever) with water," and said: "Fever is from the steam of Hell."