Some skeptics insist that research on homeopathy is mandatory since the exceptionally small doses used do not make sense and there is no known mechanism for action for these drugs. While it is true that homeopaths presently do not know precisely how the homeopathic microdoses work, there are some compelling theories about their mechanism of action (see the discussion in Chapter 1, "The Wisdom and Wonder of Small Doses"). More important, there is compelling evidence that they do work, as this chapter will show. And although homeopaths may not understand how their medicines work, keep in mind that leading contemporary pharmacologists readily acknowledge that there are many commonly prescribed drugs today, including aspirin and certain antibiotics, whose mechanism of action remains unknown, but this gap in knowledge has yet to stop physicians from prescribing them.

Many conventional physicians express doubt about the efficacy of homeopathy, asserting that they will "believe it when they see it." It may be more appropriate for them to acknowledge that they will "see it when they will believe it." This is not meant as a criticism of conventional physicians as much as of conventional medical thinking. The biomedical paradigm has narrowed the view of, the thinking about, and the practice of medicine to the treatment of specific disease entities with supposedly symptom-specific drugs and procedures. An integral aspect of this approach to medicine is the assumption that the larger the dose of a drug, the stronger will be its effects. While this seems to make sense on the surface, knowledgeable physicians and pharmacologists know that it isn't true. There is a recognized principle in pharmacology called the "biphasic response of drugs."¹ Rather than a drug simply having increased effects as its dose becomes larger, research has consisently shown that exceedingly small doses of a substance will have the opposite effects of large doses.

The two phases of a drug's action (thus the name "biphasic") are dose-dependent. For instance, it is widely recognized that normal medical doses of atropine block the parasympathetic nerves, causing mucous membranes to dry up, while exceedingly small doses of atropine cause increased secretions to mucous membranes.

This pharmacological principle was concurrently discovered in the 1870s by two separate researchers, Hugo Schulz, a conventional scientist, and Rudolf Arndt, a psychiatrist and homeopath. Initially called the Arndt-Schulz law, this principle is still widely recognized, as witnessed by the fact that it is commonly listed in medical dictionaries under the definition of "law."