Sahih Bukhari Volume 5, Book 64, Hadith 4441

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.

Narrated By 'Aisha : Whenever Allah's Apostle became ill, he used to recite the Muawidhatan 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 blow and made the hand of the Prophet pass over his body.