Sahih al-Bukhari 4439
Narrated Aisha:
Whenever Allah's Messenger (ﷺ) became ill, he used to recite the Muawidhatan (i.e. the last two surahs of the Qur'an) and blow his breath over himself (after their recitation ) and rubbed his hands over his body. So when he was afflicted with his 
fatal illness. I started reciting the Muawidhatan and blowing my breath over him as he used to do and then I rubbed the hand of the Prophet (ﷺ) over his body.
حَدَّثَنِي حِبَّانُ، أَخْبَرَنَا عَبْدُ اللَّهِ، أَخْبَرَنَا يُونُسُ، عَنِ ابْنِ شِهَابٍ، قَالَ أَخْبَرَنِي عُرْوَةُ، أَنَّ عَائِشَةَ ـ رضى الله عنها ـ أَخْبَرَتْهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ إِذَا اشْتَكَى نَفَثَ عَلَى نَفْسِهِ بِالْمُعَوِّذَاتِ وَمَسَحَ عَنْهُ بِيَدِهِ فَلَمَّا اشْتَكَى وَجَعَهُ الَّذِي تُوُفِّيَ فِيهِ طَفِقْتُ أَنْفِثُ عَلَى نَفْسِهِ بِالْمُعَوِّذَاتِ، الَّتِي كَانَ يَنْفِثُ، وَأَمْسَحُ بِيَدِ النَّبِيِّ صلى الله عليه وسلم عَنْهُ‏.‏