Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
ahmad:6010 – Hāshim > Jasr > Salīṭ > Ibn ʿUmar

[Machine] The Messenger of Allahﷺ said: "When you feel a fever, extinguish it with cold water."  

أحمد:٦٠١٠ – حَدَّثَنَا هَاشِمٌ حَدَّثَنَا جَسْرٌ حَدَّثَنَا سَلِيطٌ عَنْ ابْنِ عُمَرَ قَالَ

قَالَ رَسُولُ اللهِ ﷺ إِذَا أَحْسَسْتُمْ بِالْحُمَّى فَأَطْفِئُوهَا بِالْمَاءِ الْبَارِدِ  

See similar narrations below:

Collected by Ṭabarānī
tabarani:4399 – [Chain 1] al-ʿAbbās b. al-Faḍl al-Asfāṭī > Abū al-Walīd al-Ṭayālisī [Chain 2] Abū Ḥuṣayn al-Qāḍī > Yaḥyá al-Ḥimmānī > Abū al-Aḥwaṣ > Saʿīd b. Masrūq > ʿAbāyah b. Rifāʿah > Rāfiʿ b. Khadīj

Fever is from the vehement raging of the fire of Hell, so extinguish it with water. (Using translation from Muslim 2209c)   

الطبراني:٤٣٩٩ – حَدَّثَنَا الْعَبَّاسُ بْنُ الْفَضْلِ الْأَسْفَاطِيُّ ثنا أَبُو الْوَلِيدِ الطَّيَالِسِيُّ ح وَحَدَّثَنَا أَبُو حُصَيْنٍ الْقَاضِي ثنا يَحْيَى الْحِمَّانِيُّ قَالَا ثنا أَبُو الْأَحْوَصِ عَنْ سَعِيدِ بْنِ مَسْرُوقٍ عَنْ عَبَايَةَ بْنِ رِفَاعَةَ عَنْ رَافِعِ بْنِ خَدِيجٍ قَالَ

قَالَ رَسُولُ اللهِ ﷺ «الْحُمَّى مِنْ فَيْحِ جَهَنَّمَ فَأَطْفِئُوهَا بِالْمَاءِ الْبَارِدِ»