Indeed, this practice has no basis in either the Qur’an or the Sunnah. It is no more than an innovation or bid`ah and hence it should be avoided.
Sheikh Ahmad Kutty senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states the following: “We should stay away from such practices that are not based on explicit proofs from the Qur’an or the authentic Sunnah of the Prophet (peace and blessings be upon him).
We can use the Qur’an as a source of healing by reading it and blowing on ourselves or on those who are afflicted. The Prophet (peace and blessings be upon him) used to read Surahs al-Ikhlas, al-Falaq, and an-Nas into his cupped hands, blow into his hands, and then wipe over his body. We don’t have any mention of the Prophet (peace and blessings be upon him) recommending to anyone to write the Qur’an on a board and then wash it and drink the water. Thus, it is better to stay away from such innovations, as every innovation, especially in matters of religion, is a source of deviation.
Indeed, we have sufficiency in the prescribed sources and in the permissible treatments; therefore, we are in no need of resorting to such questionable practices.”