Homeopathy, or homeopathic medicine, is an early nineteenth-century system of diagnosis and treatment that predates the modern germ theory of disease. At the time, medicine was still quite primitive, and it was largely based on the humoral theory of disease that dated back to Galen and Hippocrates. Many diseases were believed to be caused by “bad blood,” for example, and were thus treated through the removal of some of the offending substance. Quite a few toxic substances were used as medicines as well; for instance, the use of mercury as a prescription for syphilis was responsible for at least some of the mental deterioration associated with the later stages of the disease. In that era a treatment approach that was guaranteed to do no harm was certain to prove popular, and so German physician Samuel Hahnemann (1755–1843) found a ready audience for homeopathy.
According to homeopathic theory, sometimes referred to as the Law of Similars, a physical or psychological symptom can be cured by administering an ingredient that causes that symptom in a healthy person. Hahnemann was apparently inspired in this by the use of quinine to treat malaria. It helps, but it also produces fevers in a healthy individual. In the world of homeopathy, “like cures like,” and so treatment consists of identifying the person’s symptoms, identifying an ingredient that would cause those symptoms, and administering that ingredient as a medicine. On the surface, this sounds absurd: treating a poisoned person by administering more poison, for example, could lead to the patient’s immediate death, rather than a cure. Dr. Hahnemann believed, however, that a medicine’s curative effect actually increases as the medicine becomes more dilute. In fact, most homeopathic remedies, by deﬁnition, are so dilute that they usually don’t actually contain the active ingredient—many are diluted so far that they do not contain even a single molecule of the original substance. These are the medications that homeopaths often consider their most potent cures.
On the packaging of homeopathic remedies, the amount of dilution involved is indicated by a number followed by a multiplication sign (X). A 10X dilution (not uncommon) means the process starts with a 10:1 dilution in water: ﬁve ounces of water to a half-ounce of the active ingredient, for example. This is to be shaken thoroughly. Next 1/10 of solution is diluted 10:1 in water. Then 1/10 of that solution is diluted in 10 parts water. After following these steps eight more times, the result is a solution of 1 part in 10 million. Again, basic chemistry indicates that at those levels of dilution it is possible that not a single molecule of the original substance remains. This is not the only system of dilution used, however; some medications use a C (as in 5C, for example), to denote dilution steps of 100:1 rather than 10:1.
This is a classic example of pseudoscience because for these remedies to work, the currently well-established laws of chemistry would have to be completely wrong. Most homeopathic manuals don’t bother to explain how this might work, though some propose that the water retains a “memory” of the substance that it once contained. The basic homeopathic claim is not that the original ingredient effects a cure, but rather that the “memory” of it in the water will somehow stimulate the body to heal itself. Not only do homeopaths not deny that their medications contain no active ingredients, but this is actually a central tenet of their theory. Unfortunately, many of the people who buy these remedies are unaware of the theory behind them, simply lumping in homeopathic remedies with herbal remedies and assuming that it’s all the same thing.
There are many customers: homeopathic medicines are a $200 million a year industry in the United States alone, and they enjoy far greater popularity in India and in Great Britain and Germany, where state-funded health care plans will pay for them.
Given the unscientiﬁc basis of homeopathy, the reader may wonder why the FDA allows these remedies to be marketed. The answer is simple: the FDA has authority over the sale of drugs, but none over the sale of plain water or sugar pills. As long as the homeopathic “medicines” contain no actual medicine, the FDA is powerless, and the manufacturers can continue to claim that their products are completely safe and have no side effects; there are very few substances about which that statement may be made, but pure water is certainly one of them. Recent developments in supplement regulation have led to full disclosure on the labels of one category of homeopathic remedy, however: those in which the diluted ingredient is ephedra (or ma huang), the herbal stimulant that was banned for U.S. sales in the spring of 2004. It is now illegal to sell any preparation that contains ephedra, even highly diluted ephedra. A recent perusal of labels on a grocery-store shelf turned up a homeopathic anti-snoring spray in which the special substance was ephedra. On the back label, where the dilution information appeared, it was accompanied by a ﬁne-print disclaimer noting that, due to dilution, this product contained no ephedra.
- Carroll, R. T. The Skeptic’s Dictionary. New York: Wiley, 2003;
- Gardner, Martin. Fads and Fallacies in the Name of Science. New York: Dover, 1957.