Why not test it by giving an entire city homeopathic water?
1. Strap the king James Bible to a wrench.
2. Bang on the main water pipe into town.
All ailments now cured!
The water will at some point in Earth's history have been in contact with every imaginable element and compound, and remember them. Thus it contains every possible homeopathic remedy, including those not yet discovered.
Therefore it will cure every possible disease, including those not yet discovered, in the population of people who have not sinned by harming their body with bad thoughts, Big Pharma, or lite beer. Anyone remaining sick is thus a sinner and must be punished.
What, you object? A witch! Vexatious!