Sahih Bukhari Volume 7, Book 70, Hadith Number 579.

Narrated By ‘Aisha : Whenever Allah’s Apostle paid a visit to a patient, or a patient was brought to him, he used to invoke Allah, saying, “Take away the disease, O the Lord of the people! Cure him as You are the One Who cures. There is no cure but Yours, a cure that leaves no disease.”