What is the ruling of the Sharia on using water over which the Qur’an and supplications have been recited, for drinking and bathing, in order to find out if one is afflicted with magic, and is this considered a weakness of faith?

The Quran, supplications (Du'a), and remembrance of Allah (Dhikr) are effective cures for magic. Some scholars have permitted ruqyah (exorcism/recitation) in water and drinking it, such as Imam Ahmad and others.

Vomiting is a type of treatment to expel illness from the body. There is no harm in seeking treatment from a religious man with correct beliefs.