What is the ruling on writing the Qur'an with saffron, then washing it and drinking it with the intention of healing? Is it permissible to recite the Qur'an over water for drinking? And what are the references or names of the early scholars who permitted this?

Writing the Qur’an with saffron or other substances, then washing it and drinking the water, or reciting the Qur’an into water and then drinking it for healing is permissible. There are narrations to this effect from the Salaf. Among the useful references in this field are: the book "Protection of Man from Jinn and Satan" and the book "The Decisive Sword Against Sorcerers and Evil Ones" by Sheikh Wahid Abd Al-Salam Bali.