The way homoepaths determine what effect their remedies have, is also interesting, and just as worthless as every other aspect of their practice.
They expose healthy individuals to the remedy, and then they note down everything that this person experiences. This is called “proving” (in itself an interesting choice of word, because there is some mild built-in deception). The provers can experience headache, pains, dizziness, feelings of unease etc., and every one of these results are regarded as symptoms that the remedy can cure in an ill person.
In this way, you can get any remedy cure anything you want, and especially want you expect it to cure. The “Berlin Wall” remedy, for instance, was able to cure a “feeling of being oppressed”. If a prover was in fact ill without knowing it, the effect of the remedy could take an unexpected turn.