Nafi' bin Yazid (may Allah have mercy on him) asked Yahya bin Sa'id (may Allah have mercy on him) about ruqyah and Qur'anic amulets, and he said: Sa'id bin al-Musayyib (may Allah have mercy on him) used to order the hanging of Qur'anic amulets, and would say: There is no harm in it.
The Shaykh said: Ruqyah whose content is not known, or which is from the ruqyahs of the time of ignorance, is not permissible; but ruqyah performed with the Book of Allah or the remembrance of Allah, while holding the belief that healing comes from Allah, has no harm in it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19612