Sahih Bukhari Volume 5, Book 59, Hadith Number 714.

Narrated By ‘Aisha : Whenever Allah’s Apostle became ill, he used to recite Al-Muawidhatan (i.e. the last two Suras of the Qur’an) and then blow his breath and passed his hand over himself. When he had his fatal illness, I started reciting Al-Muawidhatan and blowing my breath over him as he used to do, and then I rubbed the hand of the Prophet over his body.