The Qur'an is the words of Allah which is the power of Allah against anything including disease. For example, Jibril ruqyah, Jibril meruqyah with prayer which is in the name of Allah. The meaning is that the prayer becomes noble because it is in the name of Allah, Lord of the worlds.
The Qur'an is Syifa and also Furqon, when the Qur'an is read to a body that is controlled by Satan, Satan will panic, make pain even overwhelm the spirit. Then after that, our enemy begins to appear, namely the devil.