The classic explanation of why and how Homeopathy works is that the, symptommaticly catagorized, Remedies qualities, are concentrated at etheric levels, but rendered absent from the physical,(by extreme graduated dilution and purcussion). Which in use, works on the more primal mind body existance, the etheric.
Similar to physical vaccinations, yet safe because, while the Homeopathic Remedies are often created from toxins, we are only affecting our non physical system.
In that triggering of etheric reaction to known physical symptoms, the etheric life of the illness and its physical reality are severly challanged, if not erradicated, and thus our physical immune system's actions are dramaticly assisted.