Al-Zuhri narrated from Urwah, from Hakim bin Hizam (may Allah be pleased with him), that he said: O Messenger of Allah! The incantations (ruqyah) we used to have recited over us, and the medicines with which we used to treat ourselves, can they avert anything of the decree of Allah? He (peace and blessings be upon him) said: "They too are part of the decree of Allah, the Mighty and Majestic."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3077