Homeopathy (homeopathic medicine) is one of the most commonly used forms of complementary or alternative medical treatment around the world, in part because its remedies are nontoxic and typically inexpensive. Yet it also has no sound scientific basis and independent studies have repeatedly found no evidence that homeopathy works. That judgment was reinforced in March 2015 with the release of a report by the National Health and Medical Research Council (NHMRC) of the Australia Government, the largest study of its kind, which concluded that “there are no health conditions for which there is reliable evidence that homeopathy is effective.” See also: Toxicology

Homeopathy has sometimes been called Hahnemannism, after the German physician Samuel Hahnemann (1755-1843), who first articulated its principles as an alternative to the crude state of medicine in his time. Its core tenets are scientifically and medically unconventional. The first is that “like cures like”: that diseases can be treated by administering very small doses of substances that elicit similar symptoms in healthy people. Homeopathic practitioners maintain these treatments stimulate the body’s self-healing mechanisms much as vaccines help to protect against infectious diseases—even though homeopathic drugs explicitly cannot work as vaccines do. A second homeopathic principle is the “law of minimum dose,” the claim that the effectiveness of the administered compound increases along with its dilution in solution. Some homeopathic preparations are so dilute that on average no molecules of the original substance can be found in them. Homeopathic practitioners nevertheless maintain that the vigorous shaking that accompanies the mixture of their remedies impresses a “memory” of the diluted substance on the water or other solvent. This concept is contrary to known laws of physics and chemistry. See also: Vaccination

Substances used in homeopathic remedies include such naturally occurring compounds as alfalfa, belladonna, and mercury(II) cyanide, in addition to the occasional more peculiar and arbitrary materials such as bits of the Berlin Wall. Despite the inclusion of herbal active ingredients in some homeopathic remedies, homeopathy should not be confused with herbal medicine, which has a different and much older history in many cultures, although its claims are also sometimes scientifically questionable. See also: Alfalfa; Belladonna

To evaluate the effectiveness of homeopathy, the NHMRC combed the medical literature and identified 57 systematic reviews of homeopathy, covering 176 individual studies and 61 different medical conditions. After weighing the evidence, the authors of the report concluded: “No good-quality, well-designed studies with enough participants for a meaningful result reported either that homeopathy caused greater health improvements than placebo, or caused health improvements equal to those of another treatment.” They also wrote: “Homeopathy should not be used to treat health conditions that are chronic, serious, or could become serious. People who choose homeopathy may put their health at risk if they reject or delay treatments for which there is good evidence for safety and effectiveness. People who are considering whether to use homeopathy should first get advice from a registered health practitioner.” See also: Medicine; Pharmacology

In the United States, the Food and Drug Administration (FDA) regulates homeopathic preparations but does not evaluate them for safety or effectiveness. Because of the growing market for homeopathic remedies and concerns over the introduction of dangerously ineffective products, such as homeopathic vaccines and asthma treatments, the FDA held public hearings in April 2015 to gather information on the use of products labeled as homeopathic. Whether these hearing will result in any change in the regulations by the FDA remains to be seen. See also: Asthma