I used to sit with Ibn Abbas in Mecca when a fever took hold of me. He said, "Cool it down with Zamzam water, for the Messenger of Allah ﷺ said, 'Fever is from the heat of Hell, so cool it down with water,'" or he said, "with Zamzam water."
كنت أجالس ابن عباس بمكة فأخذتني الحمى فقال: أبردها عنك بماء زمزم فإن رسول الله ﷺ قال: الحمى من فيح جهنم فأبردوها بالماء- أو قال: - بماء زمزم
Bukhari narrated it in the Book of the Beginning of Creation (3261), from Abdullah bin Muhammad, who said, Abu Amir Aqadi narrated to us, who said, Hammam (he is Ibn Yahya) narrated to us, from Abu Hurairah, and he mentioned it.