Abu Jamrah narrates: I used to prevent people from coming to Abdullah bin Abbas (may Allah be pleased with them both) and bothering him. Once, I did not come for a few days, so he inquired, "Why did you not come?" I replied, "Because of fever." He said, "The Prophet (peace and blessings be upon him) said: 'Indeed, fever is a portion of the heat of Hell, so cool it with Zamzam water.'"
Hadith Referenceصحیح ابن حبان / كتاب الطب / 6068
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - انظر ما قبله.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط الشيخين