Homeopathy (also homœopathy or homoeopathy; from the Greek ὅμοιος, hómoios, "similar" + πάθος, páthos, "suffering" or "disease") is a form of alternative medicine first defined by Samuel Hahnemann in the 18th century. A central thesis of homeopathy is that an ill person can be treated using a substance that can produce, in a healthy person, symptoms similar to those of the illness. Practitioners select treatments according to a patient consultation that explores the physical and psychological state of the patient, both of which are considered important to selecting the remedy. According to homeopaths, serial dilution, with shaking between each dilution, removes the toxic effects of the substance, while the essential qualities are retained by the diluent (water, sugar, or alcohol).
Claims to the efficacy of homeopathic treatment beyond the placebo effect are unsupported by the collective weight of scientific and clinical evidence. Common homeopathic preparations are often indistinguishable from the pure diluent because the purported medicinal compound is diluted beyond the point where there is any likelihood that molecules from the original solution are present in the final product; the claim that these treatments still have any pharmacological effect is thus scientifically implausible and violates fundamental principles of science, including the law of mass action. Critics also object that the number of high-quality studies that support homeopathy is small, the conclusions are not definitive, and duplication of the results, a key test of scientific validity, has proven problematic at best. The lack of convincing scientific evidence supporting its efficacy and its use of remedies without active ingredients have caused homeopathy to be regarded as pseudoscience or quackery.
Homeopathic remedies are generally considered safe, with rare exceptions, although homeopaths have been criticized for putting patients at risk by advising them to avoid conventional medicine, such as vaccinations, anti-malarial drugs and antibiotics. Regardless of whether homeopathic preparations are effective, they may make people feel better via the placebo effect. Thus, like any placebo, such remedies may improve symptoms subject to psychological or behavioral influences such as chronic pain, fatigue, anxiety or depression. In many countries, the laws that govern the regulation and testing of conventional drugs do not apply to homeopathic remedies. Current usage around the world varies from two percent of people in the United Kingdom and the United States using homeopathy in any one year to 15 percent in India, where it is considered part of Indian traditional medicine. In the UK, the National Health Service runs five homeopathic hospitals, and in the 1990s, between 5.9 and 7.5 percent of English family doctors are reported to have prescribed homeopathic remedies, a figure rising to at least 12 percent in Scotland. However, the number of homeopathic remedies prescribed by GPs in England dropped by over 40% between 2005 and 2007, with homeopathy accounting for only 0.006% of the total prescribing budget. In 2005, around 100,000 physicians used homeopathy worldwide, making it one of the most popular and widely used complementary therapies.
Samuel Hahnemann conceived of homeopathy while translating a medical treatise by Scottish physician and chemist William Cullen into German. Being sceptical of Cullen’s theory concerning cinchona’s action in malaria, Hahnemann ingested some of the bark specifically to see if it cured fever "by virtue of its effect of strengthening the stomach". Upon ingesting the bark, he noticed few stomach symptoms, but did experience fever, shivering and joint pain, symptoms similar to some of the early symptoms of malaria, the disease that the bark was ordinarily used to treat. From this, Hahnemann came to believe that all effective drugs produce symptoms in healthy individuals similar to those of the diseases that they can treat. This later became known as the "law of similars", the most important concept of homeopathy. The term "homeopathy" was coined by Hahnemann and first appeared in print in 1807, although he began outlining his theories of "medical similars" in a series of articles and monographs in 1796.
Hahnemann began to test what effects substances produced in humans, a procedure which would later become known as "homeopathic proving". These time-consuming tests required subjects to clearly record all of their symptoms as well as the ancillary conditions under which they appeared. Hahnemann saw this data as a way of identifying substances suitable for the treatment of particular diseases. The first collection of provings was published in 1805 and a second collection of 65 remedies appeared in his book, Materia Medica Pura, in 1810. Hahnemann believed that large doses of drugs that caused similar symptoms would only aggravate illness, and so he advocated extreme dilutions of the substances; he devised a technique for making dilutions that he believed would preserve a substance's therapeutic properties while removing its harmful effects, proposing that this process aroused and enhanced "spirit-like medicinal powers held within a drug". He gathered and published a complete overview of his new medical system in his 1810 book, The Organon of the Healing Art, whose 6th edition, published in 1921, is still used by homeopaths today.
In the early 19th century, homeopathy began to be criticised. Sir John Forbes, physician to Queen Victoria, said the extremely small doses of homeopathy were regularly derided as useless, laughably ridiculous and "an outrage to human reason". James Young Simpson said of the highly diluted drugs: "No poison, however strong or powerful, the billionth or decillionth of which would in the least degree affect a man or harm a fly. Nineteenth century American physician and author Oliver Wendell Holmes, Sr. was also a vocal critic of homeopathy and published an essay in 1842 entitled Homœopathy, and its kindred delusions. The last school in the U.S. exclusively teaching homeopathy closed in 1920.
Hahnemann's miasm theory remains disputed and controversial within homeopathy even in modern times. In 1978, Anthony Campbell, then a consultant physician at The Royal London Homeopathic Hospital, criticised statements by George Vithoulkas claiming that syphilis, when treated with antibiotics, would develop into secondary and tertiary syphilis with involvement of the central nervous system. This conflicts with scientific studies, which indicate that penicillin treatment produces a complete cure of syphilis in more than 90% of cases. Campbell described this as "a thoroughly irresponsible statement which could mislead an unfortunate layman into refusing orthodox treatment".
Originally Hahnemann presented only three miasms, of which the most important was "psora" (Greek for itch), described as being related to any itching diseases of the skin, supposed to be derived from suppressed scabies, and claimed to be the foundation of many further disease conditions. Hahnemann claimed psora to be the cause of such diseases as epilepsy, cancer, jaundice, deafness, and cataracts. Since Hahnemann's time, other miasms have been proposed, some replacing one or more of psora's proposed functions, including tubercular miasms and cancer miasms.
Three potency scales are in regular use in homeopathy. Hahnemann created the centesimal or "C scale", diluting a substance by a factor of 100 at each stage. The centesimal scale was favored by Hahnemann for most of his life. A 2C dilution requires a substance to be diluted to one part in one hundred, and then some of that diluted solution is diluted by a further factor of one hundred. This works out to one part of the original solution mixed into 9,999 parts (100 × 100 −1) of the diluent. A 6C dilution repeats this process six times, ending up with the original material diluted by a factor of 100-6=10-12. Higher dilutions follow the same pattern. In homeopathy, a solution that is more dilute is described as having a higher potency. More dilute substances are considered by homeopaths to be stronger and deeper-acting remedies. The end product is often so diluted that it is indistinguishable from the dilutant (pure water, sugar or alcohol).
|X Scale||C Scale||Ratio||Note|
|1X||—||1:10||described as low potency|
|2X||1C||1:100||called higher potency than 1X by homeopaths|
|8X||4C||10-8||allowable concentration of arsenic in US drinking water|
|24X||12C||10-24||Has a 60% probability of containing one molecule of original material.|
|60X||30C||10-60||Dilution advocated by Hahnemann for most purposes: this would require two billion doses per second to six billion people for 4 billion years to deliver a single molecule of the original material.|
|400X||200C||10-400||Dilution of popular homeopathic flu remedy Oscillococcinum|
Hahnemann advocated 30C dilutions for most purposes (that is, dilution by a factor of 1060). A popular homeopathic treatment for the flu is a 200C dilution of duck liver, marketed under the name Oscillococcinum.
Commonly, critics of homeopathy, as well as homeopaths themselves, attempt to illustrate the dilutions involved in homeopathy with examples. Hahnemann is reported to have joked that a suitable procedure to deal with an epidemic would be to empty a bottle of poison into Lake Geneva, if it could be succussed 60 times. Another example given by a critic of homeopathy states that a 12C solution is equivalent to a "pinch of salt in both the North and South Atlantic Oceans", which is approximately correct. One third of a drop of some original substance diluted into all the water on earth would produce a remedy with a concentration of about 13C. Some homeopaths developed a decimal scale (D or X), diluting the substance to ten times its original volume each stage. The D or X scale dilution is therefore half that of the same value of the C scale; for example, "12X" is the same level of dilution as "6C". Hahnemann never used this scale but it was very popular throughout the 19th century and still is in Europe. This potency scale appears to have been introduced in the 1830s by the American homeopath, Constantine Hering. In the last ten years of his life, Hahnemann also developed a quintamillesimal (Q) or LM scale diluting the drug 1 part in 50,000 parts of diluent. A given dilution on the Q scale is roughly 2.35 times its designation on the C scale. For example a remedy described as "20Q" has about the same concentration as a "47C" remedy.
Not all homeopaths advocate extremely high dilutions. Many of the early homeopaths were originally doctors and generally tended to use lower dilutions such as "3X" or "6X", rarely going beyond "12X". The split between lower and higher dilutions followed ideological lines with the former stressing pathology and a strong link to conventional medicine, while the latter emphasised vital force, miasms and a spiritual interpretation of disease.
During the process of proving, Hahnemann used healthy volunteers who were given remedies, often in molecular doses, although he later advocated proving with remedies at a 30C dilution, and the resulting symptoms were compiled by observers into a "Drug Picture". During the process the volunteers were observed for months at a time and were made to keep extensive journals detailing all of their symptoms at specific times during the day. During the tests volunteers were forbidden from consuming coffee, tea, spices, or wine. They were also not allowed to play chess, because Hahnemann considered it to be "too exciting", though they were allowed to drink beer and were encouraged to moderately exercise. After the experiments were over, Hahnemann made the volunteers offer their hands and take an oath swearing that what they reported in their journals was the truth, at which time he would interrogate them extensively concerning their symptoms.
Provings have been described as important in the development of the clinical trial, due to their early use of simple control groups, systematic and quantitative procedures, and some of the first application of statistics in medicine. The lengthy records of self-experimentation by homeopaths have occasionally proven useful in the development of modern drugs: For example, evidence nitroglycerin might be useful as a treatment for angina was discovered by looking through homeopathic provings, though homeopaths themselves never used it for that purpose at that time. The first recorded provings were published by Hahnemann in his 1796 Essay on a new principle. His Fragmenta de viribus (1805) contained the results of 27 provings, and his 1810 Materia Medica Pura contained 65. For James Tyler Kent's 1905 Lectures on Homoeopathic Materia Medica, 217 remedies underwent provings and newer substances are continually added to contemporary versions.
A compilation of reports of many homeopathic provings is known as a homeopathic materia medica. In practice the usefulness of such a compilation is limited because a practitioner does not need to look up the symptoms for a particular remedy, but rather to explore the remedies for a particular symptom. This need is filled by the homeopathic repertory, which is an index of symptoms, listing after each symptom those remedies that are associated with it. Repertories are often very extensive and may include data from clinical experience in addition to provings. There is often lively debate among the compilers of a repertory and interested practitioners over the veracity of a particular inclusion. The first symptomatic index of the homeopathic materia medica was arranged by Hahnemann. Soon after, one of his students Clemens von Bönninghausen, created the Therapeutic pocket book, another homeopathic repertory. The first such Homeopathic Repertory was Dr. George Jahr's Repertory, published in 1835 in German and then again in 1838 in English and edited by Dr. Constantine Hering. This version was less focused on disease categories and would be the forerunner to Kent's later works. It consisted of three large volumes. Such repertories increased in size and detail as time progressed.
Some diversity in approaches to treatments exists among homeopaths. "Classical" homeopathy generally involves detailed examinations of a patient's history and infrequent doses of a single remedy as the patient is monitored for improvements in symptoms, while "clinical" homeopathy involves combinations of remedies to address the various symptoms of an illness.
"Remedy" is a technical term used in homeopathy to refer to a substance prepared with a particular procedure and intended for treating patients. Homeopathic practitioners rely on two types of reference when prescribing remedies: Materia medicae and repertories. A homeopathic Materia medica is a collection of "drug pictures", organised alphabetically by remedy, that describes the symptom patterns associated with individual remedies. A homeopathic repertory is an index of disease symptoms that lists remedies associated with specific symptoms.
Homeopathy uses many animal, plant, mineral, and synthetic substances in its remedies. Examples include Natrum muriaticum (sodium chloride or table salt), Lachesis muta (the venom of the bushmaster snake), Opium, and Thyroidinum (thyroid hormone). Homeopaths also use treatments called nosodes (from the Greek nosos, disease) made from diseased or pathological products such as fecal, urinary, and respiratory discharges, blood, and tissue. Homeopathic remedies prepared from healthy specimens are called Sarcodes.
Some modern homeopaths have considered more esoteric substances, known as "imponderables" because they do not originate from a material but from electromagnetic energy presumed to have been "captured" by alcohol or lactose. Examples include X-rays, sunlight, and electricity. Recent ventures by homeopaths into even more esoteric substances include thunderstorms (prepared from collected rainwater). Today there are about 3,000 different remedies commonly used in homeopathy. Some homeopaths also use techniques that are regarded by other practitioners as controversial. These include paper remedies, where the substance and dilution are written on a piece of paper and either pinned to the patient's clothing, put in their pocket, or placed under a glass of water that is then given to the patient, as well as the use of radionics to prepare remedies. Such practices have been strongly criticised by classical homeopaths as unfounded, speculative and verging upon magic and superstition.
Practitioners of homeopathy contend that higher dilutions (fewer potential molecules in each dose) result in stronger medicinal effects. This idea is inconsistent with the observed dose-response relationships of conventional drugs, where the effects are dependent on the concentration of the active ingredient in the body. This dose-response relationship has been confirmed in multitudinous experiments on organisms as diverse as nematodes, rats, and humans.
since the least amount of a substance in a solution is one molecule, a 30C solution would have to have at least one molecule of the original substance dissolved in a minimum of 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 molecules of water. This would require a container more than 30,000,000,000 times the size of the Earth.
Park has also noted that "to expect to get even one molecule of the 'medicinal' substance allegedly present in 30X pills, it would be necessary to take some two billion of them, which would total about a thousand tons of lactose plus whatever impurities the lactose contained". The laws of chemistry state that there is a limit to the dilution that can be made without losing the original substance altogether. This limit, which is related to Avogadro's number, is roughly equal to homeopathic potencies of 12C or 24X (1 part in 1024).
Research on medical effectiveness
The effectiveness of homeopathy has been a point of contention since its inception, and researchers have subjected the system to close scrutiny. One of the earliest studies concerning homeopathy was sponsored by the British government during World War II in which volunteers tested the effectiveness of homeopathic remedies against diluted mustard gas burns. More recent controlled clinical trials on homeopathy are not particularly convincing. For example NCCAM says: Positive results have been reported, but no single model has been sufficiently widely replicated, local models proposed are far from convincing, and the nonlocal models proposed would predict that it is impossible to nail down homeopathic effects with direct experimental testing. For example, while some reports presented data that suggested hoemopathic treatment of allergy was more effective than placebo, subsequent studies have questioned the conclusions.
Meta-analyses, in which large groups of studies are analysed and conclusions drawn based on the results as a whole, have been used to evaluate the effectiveness of homeopathy. Early meta-analyses investigating homeopathic remedies showed slightly positive results among the studies examined, but such studies have warned that it was impossible to draw firm conclusions due to low methodological quality and difficulty in controlling for publication bias in the studies reviewed. One of the positive meta-analyses, by Linde, et al, was later corrected by the authors, who wrote:The evidence of bias [in homeopathic trials] weakens the findings of our original meta-analysis. Since we completed our literature search in 1995, a considerable number of new homeopathy trials have been published. The fact that a number of the new high-quality trials... have negative results, and a recent update of our review for the most “original” subtype of homeopathy (classical or individualized homeopathy), seem to confirm the finding that more rigorous trials have less-promising results. It seems, therefore, likely that our meta-analysis at least overestimated the effects of homeopathic treatments.
In 2001, a meta-analysis of clinical trials on the effectiveness of homeopathy concluded that earlier clinical trials showed signs of major weakness in methodology and reporting, and that homeopathy trials were less randomized and reported less on dropouts than other types of trials.
In 2005, a systematic review of publications suggested that mainstream journals had a publication bias against clinical trials showing positive results, and viceversa on the CAM journals, although it's probably an involuntary bias. A possible submission bias was also suggested, in which positive trials tend to be sent to CAM journals and negatives ones to mainstream journals. It also noted that the reviews on all journals approached the matter on an impartial manner, although most of the reviews on CAM journals avoided noting the lack of plausibility, unlike the ones on mainstream journals who almost always mentioned it.
In 2005, The Lancet medical journal published a meta-analysis of 110 placebo-controlled homeopathy trials and 110 matched conventional-medicine trials based upon the Swiss government's Program for Evaluating Complementary Medicine, or PEK. The study concluded that its findings were compatible with the notion that the clinical effects of homeopathy are nothing more than placebo effects..
A 2006 meta-analysis of six trials evaluating homeopathic treatments to reduce cancer therapy side effects following radiotherapy and chemotherapy found "encouraging but not convincing" evidence in support of homeopathic treatment. Their analysis concluded that there was "insufficient evidence to support clinical efficacy of homeopathic therapy in cancer care".
The Cochrane Library found insufficient clinical evidence to evaluate the efficacy of homeopathic treatments for asthma or dementia, or for the use of homeopathy in induction of labor. Other researchers found no evidence that homeopathy is beneficial for osteoarthritis, migraines or delayed-onset muscle soreness.
Health organisations such as UK's National Health Service, the American Medical Association, and the FASEB have issued statements of their conclusion that there is no convincing scientific evidence to support the use of homeopathic treatments in medicine.
Clinical studies of the medical efficacy of homeopathy have been criticised by some homeopaths as being irrelevant because they do not test "classical homeopathy". There have, however, been a number of clinical trials that have tested individualized homeopathy. A 1998 review found 32 trials that met their inclusion criteria, 19 of which were placebo-controlled and provided enough data for meta-analysis. These 19 studies showed a pooled odds ratio of 1.17 to 2.23 in favor of individualized homeopathy over the placebo, but no difference was seen when the analysis was restricted to the methodologically best trials. The authors concluded "that the results of the available randomized trials suggest that individualized homeopathy has an effect over placebo. The evidence, however, is not convincing because of methodological shortcomings and inconsistencies."
Jack Killen, acting deputy director of the National Center for Complementary and Alternative Medicine, says homeopathy "goes beyond current understanding of chemistry and physics." He adds: "There is, to my knowledge, no condition for which homeopathy has been proven to be an effective treatment."
Research on effects in other biological systems
While some articles have suggested that homeopathic solutions of high dilution can have statistically significant effects on organic processes including the growth of grain, histamine release by leukocytes, and enzyme reactions, such evidence is disputed since attempts to replicate them have failed.
In 1987, French immunologist Jacques Benveniste submitted a paper to the journal Nature while working at INSERM. The paper purported to have discovered that basophils released histamine when exposed to a homeopathic dilution of anti-immunoglobulin E, a type of white blood cell. The journal editors, sceptical of the results, requested that the study be replicated in a separate laboratory. Upon replication in four separate laboratories the study was published. Still sceptical of the findings, Nature assembled an independent investigative team to determine the accuracy of the research, consisting of Nature editor and physicist Sir John Maddox, American scientific fraud investigator and chemist Walter Stewart, and sceptic and magician James Randi. After investigating the findings and methodology of the experiment, the team found that the experiments were "statistically ill-controlled", "interpretation has been clouded by the exclusion of measurements in conflict with the claim", and concluded, "We believe that experimental data have been uncritically assessed and their imperfections inadequately reported. James Randi stated that he doubted that there had been any conscious fraud, but that the researchers had allowed "wishful thinking" to influence their interpretation of the data.
Ethical and safety issuesAs homeopathic remedies usually contain only water and/or alcohol, they are thought to be generally safe. Only in rare cases are the original ingredients present at detectable levels. In one such case, an unusually undiluted (1:100 or "2X") solution of zinc gluconate, marketed as Zicam Nasal Spray, allegedly caused a small percentage of users to lose their sense of smell. There were 340 cases settled out of court for .
Critics of homeopathy have cited other concerns over homeopathic remedies, most seriously, cases of patients of homeopathy failing to receive proper treatment for diseases that it is claimed could have been diagnosed or cured with conventional medicine. Several surveys demonstrate that some (particularly non-physician) homeopaths advise their patients against immunisation. Some homeopaths suggest that vaccines be replaced with homeopathically diluted "nosodes", created from dilutions of biological agents – including material such as vomit, feces or infected human tissues. While Hahnemann was opposed to such preparations, modern homeopaths often use them and there is no evidence to indicate they have any beneficial effects. Cases of homeopaths advising against the use of anti-malarial drugs have been identified. This puts visitors to the tropics who take this advice in severe danger, since homeopathic remedies are completely ineffective against the malaria parasite. Also, in one case in 2004, a homeopath instructed one of his patients to stop taking conventional medication for a heart condition, writing in his advice, "She just cannot take ANY drugs – I have suggested some homeopathic remedies. I feel confident that if she follows the advice she will regain her health." The patient suffered a fatal heart attack four months later, caused by this stoppage of her medication.
In 1978, Anthony Campbell, then a consultant physician at The Royal London Homeopathic Hospital, criticised statements made by George Vithoulkas to promote his homeopathic treatments. Vithoulkas stated that syphilis, when treated with antibiotics, would develop into secondary and tertiary syphilis with involvement of the central nervous system. Campbell described this as a thoroughly irresponsible statement which could mislead an unfortunate layman into refusing conventional medical treatment. This claim echoes the idea that treating a disease with external medication used to treat the symptoms would only drive it deeper into the body and conflicts with scientific studies, which indicate that penicillin treatment produces a complete cure of syphilis in more than 90% of cases.
A 2006 review by W. Steven Pray of the College of Pharmacy at Southwestern Oklahoma State University recommends that pharmacy colleges include a required course in unproven medications and therapies, that ethical dilemmas inherent in recommending products lacking proven safety and efficacy data be discussed, and that students should be taught where unproven systems such as homeopathy depart from evidence-based medicine.
Regulation and prevalence
Homeopathy is fairly common in some countries while being uncommon in others; is highly regulated in some countries and mostly unregulated in others. Regulations vary in Europe depending on the country. In some countries, there are no specific legal regulations concerning the use of homeopathy, while in others, licenses or degrees in conventional medicine from accredited universities are required. In Austria and Germany, no specific regulations exist, while France and Denmark mandate licenses to diagnose any illness or dispense of any product whose purpose is to treat any illness. Some homeopathic treatment is covered by the public health service of several European countries, including France, the United Kingdom, Denmark, and Luxembourg. In other countries, such as Belgium, homeopathy is not covered. In Austria, the public health service requires scientific proof of effectiveness in order to reimburse medical treatments, but exceptions are made for homeopathy. Two countries which formerly offered homeopathy under their public health services have withdrawn this privilege. At the start of 2004, homeopathic medications, with some exceptions, were no longer covered by the German public health service, and in June 2005, the Swiss Government, after a 5-year trial, withdrew homeopathy and four other complementary treatments, stating that they did not meet efficacy and cost-effectiveness criteria, though insurance can be bought to cover such treatments provided by a medical doctor.
- List of pseudosciences and pseudoscientific concepts
- List of homeopathic preparations
- Homeopathic dilutions
Notes and references
Associations and regulatory bodies
- British Homeopathic Association (BHA)
- European Committee for Homeopathy (ECH)
- European Council for Classical Homeopathy (ECCH)
- National Center for Homeopathy (NCH)
- "UK Pharmacists urged to 'tell the truth' about homeopathic remedies". The Guardian, .
- Homeopathy: real medicine or empty promises?. US Food and Drug Administration. .
- Questions and answers about homeopathy. National Center for Complementary and Alternative Medicine (NCCAM). .National Institutes of Health Research Report
- Stephen Barrett HomeoWatch: Your skeptical guide to homeopathic history, theories, and current practices. .
- The scientific evidence on homeopathy. American Council on Science and Health. (2000). .
- Ameke Wilhelm, Drysdale AE (transl), Dudgeon RE (ed) (1885). History of homœopathy, with an appendix on the present state of University medicine. London: E. Gould & Son.
- James Randi Homeopathy Explained. . - Portion of 2001 Princeton lecture. (Complete 2 hr 10 min 43 sec lecture.)
- John Langone "Challenging the mainstream". Time Magazine, .
- Fisher Peter, Goldacre Ben Does homeopathy work?. . A debate on the evidence on both sides with Peter Fisher, Clinical Director of the Royal London Homeopathic Hospital and Ben Goldacre, medical writer and broadcaster.