Sahih Muslim
The Book on Salutations and Greetings (Kitab As-Salam)
Book Number: 026 / Hadith Number: 5435
'A'isha reported that when Allah's Messenger (may peace be upon him) came to visit any sick he supplicated for him and said: Lord of the people, remove the malady, cure him for Thou art a great Curer. There is no cure but through Thine healing Power which leaves no trouble, and in the narration transmitted on the authority of Abu Bakr there is a slight variation of wording.