Homeopathy/PreviousVersion

Homeopathy or homoeopathy—from the Greek hómoios (similar) and páthos (suffering)—is a system of alternative medicine based on the idea that substances known to cause particular combinations of symptoms in healthy people can also, in low and specially prepared doses, help to cure people whose disease has similar symptoms.

Homeopathy is used worldwide by some medical doctors and other licensed health practitioners who use it as an alternative or a complement to conventional medical treatment for both acute and chronic ailments, by a relatively small number of licensed homeopaths, and by consumers who use it to treat common non-life-threatening acute conditions. Homeopathic medicines (referred to in this article as "remedies" to avoid confusion with conventional medicines) are widely available without the need for a doctor's prescription. Many health insurance companies provide coverage for homeopathic treatment as long as it is provided by a licensed medical doctor, although many others refuse to cover treatments they judge ineffective even when prescribed by a physician.

The consensus of medical and scientific judgment is that homeopathy is unfounded. Although many studies have reported that homeopathic remedies might be effective in particular conditions, these have mostly been small and poorly controlled. Neither of the main homeopathic principles — similars and infinitisimals — makes sense to the critical scientific mind. The "principle of similars" appears to be merely an appeal to sympathetic magic, or at best an over-generalisation of a principle that applies in only a few cases. The "principle of infinitisimals" contradicts both common sense and scientific results; there is no proven mechanism to explain how the remedies might work, given that many of them are so dilute that they contain not a single molecule of the active ingredient. Homeopaths have rejoinders to each of these arguments and consider them to be evidence of medical arrogance.

Principles of homeopathy, and their historical origins

Principles

According to homeopaths, their remedies stimulate the body's "natural healing processes" and invoke the "wisdom of the body". Remedies are derived from substances which, when given in overdose to healthy people, cause symptoms similar to those of the patient being treated; homeopaths claim that these augment the body's own defenses. Hygiene, diet, and other natural therapies are also often used by homeopaths in conjunction with remedies.

Two basic ideas in homeopathy are the principle of similars, sometimes stated as "like cures like", and the principle of infinitisimals, the idea that remedies become more potent if they undergo a process called potentization, which consists of repeated dilutions (1:10, 1:100, or 1:50,000) with vigorous shaking in-between each dilution, called succusion.

Individualization of treatment is also essential to the practice of classical homeopathy, whereby a remedy is chosen based on the person's overall 'syndrome of symptoms', not just a generic disease diagnosis.

History

The principles of homeopathy were first methodically set out by a German physician, Samuel Hahnemann (1755–1843), who observed that a medicine sometimes evoked symptoms similar to those of the illness for which it was prescribed. In homeopathic theory, every person has a "vital force", with the power to promote healing and/or maintain good health. In this theory, the signs and symptoms of a disease reflect efforts of the body to defend itself against infection, environmental assault, or various stresses. Homeopathic treatment attempts to strengthen the "vital force" with remedies chosen for their ability (in large doses) to provoke the similar symptoms that the remedy is intended to heal. Many famous people over the past 200 years have been users and advocates of homeopathy, and it is an important thread in the history of medicine.

Precursors

The early Greek physician Hippocrates of Cos (c. 450–380 BC), who is considered to be the "father of medicine", is also claimed by homeopaths as a pioneer in their own tradition—because he taught that "Natural forces within us are the true healers of disease," and because he thought that some diseases could be cured by the same things that caused them.

Hahnemann

In the early 18th century, the conventional medicine of the day has been commonly referred to as heroic medicine because its physicians often used large doses of toxic compounds in a seemingly valiant effort to save lives. Invasive procedures such as bloodletting and leeching were used indiscriminately. In 1783, disillusioned with "heroic" medicine, Hahnemann gave up his medical practice and devoted himself to translating medical books. Among them was the Treatise on Materia Medica by William Cullen, the leading physician of the 18th century.

Cullen had written that cinchona bark (which contains quinine) was effective in treating malaria because of its bitter and astringent properties. Hahnemann questioned this, because he knew that other substances were as bitter and astringent, but had no therapeutic value in this disease.

Hahnemann saw that the effects he experienced from ingesting cinchona bark were similar to the symptoms of malaria. He observed similar results with other substances, and so conceived of the law of similars, or "let like be cured by like" (Latin: similia similibus curentur). This is the assertion that a disease can be cured by remedies that (in macroscopic, milligram doses) produce the same symptoms as those of the disease, and is a guiding principle in homeopathy. Hahnemann believed that, by inducing symptoms similar to the disease, the natural healing processes of the body would be stimulated. From these ideas, he developed a new system of health care, which he named "homoeopathy" (meaning "like disease")—and coined the term "allopathy" ("different than disease") to refer to the conventional medicine of the day (heroic medicine).

For the first two decades, Hahnemann used "crude" doses of medicinal substances ("crude", in homeopathic use, means doses that still contain some of the original ingredient). He strove to find the lowest doses at which his remedies would still be effective, and he concluded that they worked better the more he diluted them as long as he “potentized” them, i.e. by serial dilution followed by vigorous shaking (succussion). Homeopathy thus became inextricably linked with ultradilution. Hahnemann had no clear explanation as to how or why these potentized remedies might have benefits; he distrusted theoretical explanations and argued that all that mattered was whether a treatment was therapeutically effective.. Hahnemann coupled his theory with a method of "provings" to determine what symptoms a substance causes and thereby what a particular remedy might cure (see below).

Education

The first homeopathic school in the U.S.A. opened in 1835, and in 1844, the first U.S. national medical association—the American Institute of Homeopathy—was established. By the end of the 19th century, 8% of American medical practitioners were homeopaths, and there were 20 homeopathic colleges and more than 100 homeopathic hospitals in the U.S.A. One reason for the growing popularity of homeopathy was its relative success in combatting the epidemics that raged at the time. Cholera, scarlet fever, typhoid fever, and yellow fever killed many people, but death rates in hospitals that used heroic medicine were typically two- to eight-fold higher than in homeopathic hospitals.

In the early 20th century, the "Flexner Report" triggered major changes in American medical education. Many medical schools, including those teaching homeopathy were closed down, while others became devoted to a new vision of a biochemical understanding of medicine that replaced the discredited heroic medicine. Nevertheless, in the 1960's, the popularity of homeopathy began to revive in the U.S.A, and a 1999 survey reported that over 6 million Americans had used homeopathy in the previous 12 months. The number of homeopathic practitioners in the U.S.A. increased from fewer than 200 in the 1970's to about 3,000 in 1996.

Conflict with conventional medicine

The theory underlying homeopathy is not considered plausible by most academic scientists, and the treatment advice offered by homeopaths is in disagreement with conventional medicine. Their view is that homeopathy exploits the placebo effect—i.e. that the only benefits are those induced by the power of suggestion, by arousing hope, and by alleviating anxiety.

Homeopaths believe that the fundamental causes of disease are internal and constitutional and that infectious disease is not just the result of infection but also of susceptibility. This respect for the body's own immune and defense systems leads them to avoid conventional treatments that suppress symptoms. Physicians consider that most diseases are caused by a combination of external causes (such as viruses, bacteria, toxins, dietary deficiency, physical injury) and physiological dysfunction of medically defined host defenses (including genetic defects and mutations such as those which trigger cancers). Goals of conventional medicine include eliminate these causes, although physicians often also use drugs both to suppress the discomfort of a disease (e.g., opioid analgesics) as well as supplementing host resistance based on specific mechanisms, such as passive and active immunization.

Prophylactic use of homeopathy

Some homeopaths believe that their treatments can prevent disease, a notion known as "'homeoprophylaxis". A 2006 survey by the U.K. charity Sense About Science revealed that homeopaths were advising travelers against taking conventional antimalarial drugs, instead recommending a homeopathic remedy. Even the director of the the Royal London Homeopathic Hospital condemned this, saying:

"I'm very angry about it because people are going to get malaria—there is absolutely no reason to think that homeopathy works to prevent malaria and you won't find that in any textbook or journal of homeopathy so people will get malaria, people may even die of malaria if they follow this advice."

Homeopathic "provings"

In homeopathic drug provings, volunteers are given repeated doses of substances (usually in single-blind or double-blind protocols), and keep a diary of any symptoms. These are later recorded in textbooks, called Materia Medica and Repertory, or nowadays in expert system software. These 'provings' provide, for homeopaths, the basis to determine what a substance causes in overdose and thereby what it is thought to cure. The symptom complexes from drug provings are compared with a patient's symptoms in order to select, as the appropriate most similar remedy, the substance whose effects are closest to the patient's symptoms—called the "simillimum". Homeopaths prescribe a remedy (in potentized doses) when a sick person has a syndrome of symptoms that resembles the syndrome of symptoms that it causes in drug proving.

In 2006, the U.K. Medicine and Healthcare Products Regulatory Agency altered their regulations to allow evidence from provings to support advertising claims for homeopathic remedies (justifying phrasing such as “For the relief of...”). Scientists protested at this, calling it a departure from the principle that such claims should be justified by evidence of efficacy.

Homeopathic remedies

In the U.S.A., the Homœopathic Pharmacopœia of the United States describes how to manufacture homeopathic remedies. Remedies listed in the HPUS are defined as "homeopathic drugs", which grants them a different standard of regulation than conventional drugs. For example, remedies are exempt from good manufacturing practice requirements related to expiration dating, and from finished product testing for identity and strength. In 1938, the federal Food, Drug, and Cosmetic Act, sponsored by Senator Royal Copeland, a former homeopathic medical school dean, gave the Food and Drug Administration (FDA) the power to regulate drugs and granted legal recognition to the HPUS. Conventional medicines for which a New Drug Application is required must be accompanied by adequate evidence of safety and efficacy. In contrast, any substance can become a homeopathic remedy.

Today, homeopaths use about 3,000 remedies, made from plants, trees, and fungi and from a wide variety of mineral and animal sources. Even some unusual substances, called imponderables, are used, including electricity, X-ray, and magnetic north and south poles. By convention, the first letter of the Latin-derived name of a remedy is capitalized. The traditional name rather than chemical, International Nonproprietary Name or biological nomenclature, is preferred, such as Natrum muriaticum rather than sodium chloride. Remedies for internal consumption come either in pill form or as liquid. Most do not need a doctor's prescription, unless the dosage is in a non-potentized or low potency dose and if the original substance is potentially toxic (in Europe, a substance must be diluted at least 1:1000 to be deemed homeopathic). In the U.S.A., if a remedy is claimed to treat a serious disease such as cancer, it can be sold only by prescription. Only remedies for “self-limiting conditions”—minor health problems that are expected to go away on their own—can be sold without a prescription.

The most characteristic principle of homeopathy is that the efficacy of a remedy can be enhanced by "dynamization" or "potentization". In this process, liquids are diluted (with water or ethanol) and shaken by ten hard strikes against an elastic body ("succussion"), to get the next, higher, potency. When insoluble solids such as oyster shell are used for remedies, they are diluted by grinding them with lactose ("trituration"). The original dilutions by Hahnemann used a 1 part in 100 (centesimal; "C" potencies), or 1 part in 50,000 (quintamillesimal; "LM" or "L" potencies). Dr Constantine Hering later introduced the Decimal potencies ("D" or "X" potencies). The dilution factor at each stage is 1:100 ("C" potencies), 1:50,000 ("LM" potencies) or 1:10 ("D" or "X" potencies); Hahnemann advocated $30C$ dilutions for most purposes (i.e. dilution by a factor of 100³⁰ = 10⁶⁰). It is extremely unlikely that even one molecule of the original substance would be present in a $30C$ dilution. Thus, liquid remedies of a high "potency"' contain just water, but according to homeopaths, the structure of the water has been altered (see memory of water); remedies in pill form contain just sugar.

Many remedies sold in health food stores and pharmacies are "low potencies," that is, doses that are 3X, 3C, 6X, 6C, 12X, and 12C, all of which, except the last dose, contain material doses of the original substances.

In many countries, remedies are sold over-the-counter in both pharmacies and health food or other retail outlets; the global self-medication market is estimated at 48.2 billion dollars (13.4% of the world pharmaceuticals market), of which sales of remedies account for 0.3%. The American Homeopathic Pharmaceutical Association, estimated the 1995 retail sales of homeopathic remedies in the U.S.A. at $201 million and growing at 20% per year. Almost 70% of all over-the-counter remedies are sold in Western Europe. France is the largest market, worth over 300 million euros in 2003 (in a total over-the-counter drug market of over 770 billion euros), followed by Germany (200 million euros).

Homeopathy in practice

Homeopathy generally scores highly in "patient satisfaction" surveys. In the U.K., a survey cited by the British Homeopathic Association found that 15% of the public "trust" homeopathy. It found even more trust in homeopathy in other countries: 58% Brazil, 53% Chile, 49% Saudi Arabia, 40% France, 28% Russia, 27% Germany, and 18% USA. That said, patient satisfaction and strength of public support for a treatment does not count as scientific evidence—just because a lot of people believe something does not make it true (see argumentum ad populum).

In Europe, homeopathic remedies are occasionally prescribed by MDs, including by 30-40% of French and 20% of German doctors. Some of this is covered by public funds; for instance, in France, 35% of the costs of homeopathic remedies prescribed by an MD are reimbursed from health insurance; in the U.K., five homeopathic hospitals are funded by the National Health Service (NHS) and homeopathic remedies are sold over the counter. In 2007, the over-the-counter market in homeopathy was around £40million in the U.K.; the total over-the-counter market was £1.2 billion in 1994. In Austria, the public health service generally requires proof of effectiveness to reimburse medical treatments, but makes an exception for homeopathy.

A typical homeopathic visit

• "Homeopathy is designed to treat the whole person and can therefore be considered in almost any situation where a person's health is depleted." (British Homeopathic Association)
• "The physician must remember that he is treating a patient who has some disorder; he is not prescribing for a disease entity." (from the American Institute of Homeopathy "Standards of Practice")

Patients often come to homeopaths with chronic problems that have not responded to conventional treatment; these include common ailments such as eczema, asthma, migraine, irritable bowel syndrome, arthritis, anxiety and depression, but homeopaths also accept patients with serious diseases, including cancer. and AIDS Homeopaths view illness as a disturbance in the 'overall homeostasis of the total being', so they believe that almost any sick person can benefit from homeopathic treatment. Most homeopaths are not medically qualified; those who are, after diagnosing a chronic condition that does not indicate the need for medical urgency, might prescribe a remedy rather than a conventional medicine which he feels may be ineffective and/or likely to have side effects. Homeopaths recognize that trauma might require conventional medical attention, but may complement that with homeopathy.

When a homeopath is conducting an interview to characterise a patient's syndrome of symptoms, some "categories of change" are identified as important: (1) emotion (2) mentation (3) specific physical functioning (4) general physical changes (5) perception of self (6) relationships (7) spirituality (8) lifestyle (9) energy (10) dream content and tone (11) well-being (12) perceptions by others (13) life relationships (14) a sense of freedom or feeling less "stuck" (15) sleep (16) coping (17) ability to adapt (18) creativity (19) recall of past experiences

In "Classical ("Hahnemannian") homeopathy, a single remedy is chosen according to the physical, emotional, and mental symptoms that the sick individual is experiencing, rather than the diagnosis of a disease. ("Commercial" or "user-friendly" homeopathy refers to the use of a mixture of remedies in a formula containing individual ingredients chosen by the manufacturer for treating specific ailments). When deciding which remedy to prescribe, classical homeopaths place emphasis on the patient's unique symptoms and their psychological state. They gather this information from an interview, typically lasting from 15 minutes to two hours, with one or more follow-up consultations of 15 to 45 minutes. They assess how the patient experiences their disease—i.e. they give priority to the overall syndrome of symptoms and the unique symptoms, unlike the conventional medical approach of trying to identify the causes of the disease. Their goal is to determine factors that might predispose the patient to disease, and find a treatment that will strengthen that patient's "overall constitution". After the interview, the homeopath consults the references described on the right. Some homeopaths make quick prescriptions based on "keynotes"—the highlights of the best known characteristics of a remedy. The real challenge of homeopathic practice is to find the remedy that best matches the patient's "syndrome of symptoms" —the "similimum".

The homeopathic treatment of acute problems does not need the same depth or breadth of interview as chronic conditions. According to homeopaths, because the symptoms of a common cold or a headache or an allergy vary from person to person, each may need a different remedy. However, they believe that people who experience an injury generally have similar symptoms, so they think that some remedies might be routinely useful in such cases. For some disease conditions, such as asthma or acute bronchitis, remedies are often prescribed not only to treat chronic symptoms, but also to treat acute attacks. Remedies might also be used after an asthmatic episode with the intent to prevent recurrences.

"Classical" homeopaths prescribe one remedy at a time—a remedy that best fits the overall syndrome of the patient. The same remedy might thus be prescribed for patients with very different diseases; conversely, patients suffering from the same disease may be prescribed different remedies. For example, hay fever would be treated with any of several remedies, usually based on the specific symptoms, but sometimes on the etiology of the allergy. Some common remedies are: Allium cepa (onion, which causes tears to flow and a clear burning nasal discharge that irritates the nostrils), Euphrasia (eyebright, which causes a clear and bland nasal discharge along with tears that burn and irritate), Ambrosia (ragweed) and Solidago (goldenrod); ragweed and goldenrod are herbs whose pollen is aggravating to some hay fever sufferers. These are commonly given during the acute symptoms of hay fever. At other times, a homeopath might treat these patients with a constitutional remedy based on the patient’s family history, health history, and overall physical and/or psychological state.

Attempts to provide a scientific foundation for homeopathy

Homeopathy arose when important concepts of modern chemistry and biology, such as molecules and germs, were understood poorly, if at all. In Hahnemann's day, many chemists believed that matter was infinitely divisible, so that it was meaningful to talk about dilution to any degree. The size of atoms was not calculated until 1865 (by Josef Loschmidt), but we now know that, a 12C dilution of a drug will have about one molecule of that substance per litre. Thus, a dose of any drug that has been diluted to more than about 12C is virtually certain to contain not a single molecule of the drug. This is recognized by homeopaths, who assert that the healing power is not in the action of molecules, but in some change in the structure of the water itself—the presumed "memory of water".

Widely differing explanations are proposed for this alleged memory. For instance, homeopaths point out that water is not simply a collection of molecules of H₂O, but contain isotopologues (molecules with different isotopic compositions such as HDO, D₂O and H₂¹⁸O). Mass spectroscopy can detect these different isotopologues, but the concentration ratios can only be changed by nuclear reactions—they are not affected by homeopathic treatment, so they cannot explain its "memory". The fact that the molecules H₂O appear in two proton-spin forms (ortho and para) has also been suggested as a source of memory of water. These spin forms, which appear in a ratio 3:1, are chemically indistinguishable and are very difficult to separate or to convert into each other, so it is highly unlikely that a homeopathic treatment could change this ratio. Even if homeopathic tinctures could give rise to ortho:para ratios other than 3:1, it requires a massive leap of imagination to envisage how this might result in different, specific healing qualities.

Some homeopaths believe that succussive shaking might lead to "clustering" of water molecules. This is not credible: motions in liquid water are on the picosecond (10⁻¹² second) timescale and such clusters could not live longer than a few picoseconds. Another suggestion is that double-distilled and deionized water contains trace amounts of contaminating ions: water, after vigorous shaking, might include dissolved atmospheric gases in the form of nanobubbles, ions produced from water reacting with airborne contaminants, and silicates—tiny glass "chips"; it's easy to see that such contamination is likely to occur, but hard to see how it could have therapeutic value

In 2009, Luc Montagnier, the Nobel Laureate virologist, claimed that highly diluted DNA from pathogenic bacterial and viral species can emit specific radio waves that might be associated with ‘nanostructures’ in the solution. The claim has been received with deep skepticism by the scientific community..

Homeopaths contend that the "principle of similars" is analagous to the concept of hormesis and is the basis for vaccination and allergy desensitation. Scientists today do not think that this 'principle' is generally true or useful, and they explain the efficacy of vaccination without referring to it. Although homeopathic remedies and vaccinations both use low doses of ingedients, the doses in remedies are very much lower than those in vaccines. Vaccines produce a measurable immune response (e.g., immunoglobulin production); homeopathic remedies do not. Thus conventional treatments involve measurable doses of substances, at levels known to activate a cellular response.

In brief, for homeopathy to receive serious scientific consideration, there must be plausible explanations for the following:

• how the process of manufacturing a homeopathic remedy could yield a biologically active substance
• why the principle of similars might apply in the case of remedies
• how a biological mechanism could have evolved to recognize the specific nature of remedies

There also needs to be compelling evidence for the efficacy of remedies, evidence that cannot be explained by placebo effects. These stringent demands are often summarised by the maxim "Extraordinary claims require extraordinary proof".

Homeopaths assert that they are up against a double standard in medicine and science. Many conventional treatments were used long before any knowledge of their mechanism of action; only recently, for instance, has it been understood how aspirin works. Aspirin was introduced around the turn of the 20th century, and medical standards have become very much more rigorous since then. If aspirin was a new drug, it would require clinical trials; Institutional Review Boards and other safety mechanisms would demand that the mechanism of action be known before authorizing these.

Safety and efficacy

Homeopaths assert that trials of efficacy, basic sciences research, historical use of remedies in infectious disease epidemics, and cost-effectiveness studies provide reasonable evidence for the benefits of homeopathy. By contrast, most scientists think that homeopathic treatments have no efficacy beyond placebo effects.

The "balance of evidence" as to whether homeopathy has any effects depends on who is doing the balancing. Homeopaths favour the evidence of their own experience in treating patients, supported by the satisfaction reported by their patients in surveys; they also (correctly) state that most published trials have reported evidence for some beneficial effects, including for postoperative ileus, allergic rhinitis, and for individualised treatment of childhood diarrhoea

According to academic critics, trials of homeopathy have been mostly small and flawed (generally lacking adequate controls and objective outcome measures). A 1991 meta-analysis in the British Medical Journal of 105 homeopathic trials recognised that most of them reported positive results, but warned that "most trials are of low methodological quality." A 1997 meta-analysis in the Lancet also noted the preponderance of positive trial results, declaring that the results were "not compatible with the hypothesis that the effects of homoeopathy are completely due to placebo." However, the same authors went on to show that larger high-quality trials tend to show little or no significant effects The most recent meta-analyses, which take study quality into account, suggest that remedies are no different to placebos

Why small trials tend to report positive outcomes while large trials are more likely to report small or no effects is generally attributed to "publication bias" – small trials with negative or inconclusive outcomes are less likely to be written up for publication, and if submitted are less likely to be accepted for publication, because they are thought to be uninteresting. In 1999, the Swiss Government, for 5 years, allowed costs for treatment with homeopathy and four other CAM modalities to be reimbursed under the country’s health insurance scheme, and set out to evaluate their cost-effectiveness. A team of scientists and practitioners, including a homeopath, conducted a meta-analysis that aroused considerable interest - and a storm of protest from homeopaths. The study, published in the Lancet took a novel approach; whereas traditional meta-analyses combine studies of a single condition, this was a "global" meta-analysis testing the hypothesis that all effects of homeopathy are placebo effects. If so, the authors reasoned, then the predominance of positive homeopathy trial reports reflects publication bias, and hence the magnitude of effects should diminish with sample size and study quality. They analyzed 110 placebo-controlled homoeopathy trials and 110 matched conventional trials. In both, effect size declined with improved study quality; however, some effect was still present in the largest and best conventional trials, but not in the largest and best homeopathy trials. The authors concluded that homeopathy was no better than placebo, and suggested that no further research on homeopathy is necessary. The article was accompanied by two editorials, one titled “The end of homeopathy”..

Homeopathic response

The Lancet published critical correspondence, and received an open letter from the 'Swiss Association of Homoeopathic Physicians' which declared:

“The meta-analysis may be statistically correct. But its validity and practical significance can be seen at a glance: not one single qualified homoeopath would ever treat one single patient in clinical practice as presented in any of the 110 analysed trials! The study cannot give the slightest evidence against homoeopathy because it does not measure real individual (classical) homoeopathy. It confounds real homoeopathic practice with distorted study forms violating even basic homeopathic rules.”

Critics of the analysis noted that several studies that had earlier been defined as "high quality" by Linde et al. (1997) were not defined by high quality in the Lancet paper by Shang et al., and most of these showed a positive effect of homeopathic treatment. The analysis also excluded a relatively large study of chronic polyarthritis (N=176) because no matching trial could be found. An article in the Journal of Clinical Epidemiology stated "This result can be interpreted differently. Following Shang's perspective it can be explained by small study bias (which includes publication bias). In contrast, one may hypothesize that Shang's result is falsely negative." The authors noted that four of the 21 'best' trials dealt with muscle soreness; these found no benefits to homeopathy, but the other 17 trials show an overall significant effect, mainly determined by two trials on influenza-like diseases. Thus, they argue, homeopathy might be effective for some conditions but not others.

Homeopaths believe that, because homeopathy does not lend itself to controlled trials, those with a negative outcome may be false negatives. They also claim that many studies in which homeopathy appears ineffective are methodologically flawed — they either did not follow proper homeopathic procedure in the selection of remedies or they did not adequately repeat the remedy.

In conventional medicine (see New Drug Application), the basic phases of evaluating a drug determine: if it causes dangerous effects in healthy volunteers; if it is adequately present in the body to achieve an effect; and if it is more effective than established treatments. Randomized controlled trials use statistical analysis of large groups of patients to determine whether a treatment given in a standardised form to one subgroup is safer and more effective than a different standardised treatment given to another. This conflicts with an approach that believes that treatments must be individually tailored to each patient. Clinical trial specialists have proposed protocols to test "low responding" or individualized therapies in statistically valid clinical trials. For homeopathy, by having a group of people who identify as ill and asking a qualified homeopath to diagnose them - then having a remedy given to a subset, and medicines that share the same physical properties but are homeopathically inert (for instance, by using ordinary water rather than homeopathically diluted water in preparing the substance). This method thus tests the standard diagnostic method as the experimental treatment, rather than the specific medications. There have not been, however, many homeopathic trials using this method.

Government and institutional assessments

In 2010, the United Kingdom House of Commons Science and Technology Committee published a report on the evidence for homeopathy. It concluded that the principle of "like-cures-like" is "theoretically weak" and "fails to provide a credible physiological mode of action for homeopathic products. We note that this is the settled view of medical science." It described the use of ultra-dilution as "scientifically implausible", and on the effectiveness of homeopathy said:

In our view, the systematic reviews and meta-analyses conclusively demonstrate that homeopathic products perform no better than placebos.

The report rejected evidence presented by the British Homeopathic Association on systematic reviews and accepted Professor Edzard Ernst's account of the weaknesses of that evidence. It stated that advocates of homeopathy had chosen "to rely on, and promulgate selective approaches to the evidence base". It rejected calls for further research:

There has been enough testing of homeopathy and plenty of evidence showing that it is not efficacious. Competition for research funding is fierce and we cannot see how further research on the efficacy of homeopathy is justified

It recommended against the use of homeopathy on the NHS even as a placebo treatment (as they concluded homeopathy to be): for a placebo to be effective, the patient must not know it is a placebo, but medical ethics requires that a patient must make an informed choice. It also advised that, if the NHS appears to endorse homeopathy, there is a danger that patients might neglect conventional medicine, with serious health consequences. The report concludes that NHS funding of homeopathic hospitals should stop, and that NHS doctors should not refer patients to homeopaths.

The report conclusions have been supported by the British Medical Association, which voted in favour of stopping any use of any NHS funds for homeopathy, and proposed that pharmacists should remove homeopathic remedies from their shelves to prevent them from being confused with medicines.

The Royal Pharmaceutical Society of Great Britain suggested that patients ought to be "made aware of the fact that there is no scientific basis for the use of homeopathy", and that unless homeopathy can be shown to be efficacious "using appropriate methodology (as for conventional medicines)" any "claims of efficacy should be removed from the label". It also concluded that "homeopathic remedies should be reviewed by NICE if they are to be used within the NHS to ensure that they give value for money" – historically, homeopathy has not been subject to review by NICE. The U.K. Government has, for now, decided to continue to allow individual doctors to prescribe homeopathic treatment on the NHS in accordance with the principle that doctors should be free to decide whatever treatment they think appropriate in individual cases.

Medical organizations' attitudes

The American Medical Association (AMA) was founded in 1847, and from the 1860s to the early 20th century, it forbade its members to consult with MDs who practiced homeopathy. Today, it is not openly antagonistic to homeopathy; their current policy states: "There is little evidence to confirm the safety or efficacy of most alternative therapies. Much of the information currently known about these therapies makes it clear that many have not been shown to be efficacious."

The National Center for Complementary and Alternative Medicine (NCCAM) funds research into alternative medicine in the U.S.A.. Their views are detailed on a signed articles page associated with this article. In 2008, NCCAM's acting deputy director said "There is, to my knowledge, no condition for which homeopathy has been proven to be an effective treatment".

In the U.K., the NHS recognizes that there have been about 200 randomised controlled trials evaluating homeopathy; some show efficacy and some don't. They conclude, "it has proven difficult to produce clear clinical evidence that homeopathy works".NHS doctors are free to decide what treatment is best for each patient, and a few do sometimes prescribe homeopathic remedies. The NHS supports several homeopathic hospitals, and in Scotland about 600 doctors treat about 55,000 patients per year at NHS homeopathic clinics.

Safety

The highest ideal of cure is the speedy, gentle, and enduring restoration of health by the most trustworthy and least harmful way (Samuel Hahnemann)

In the U.S.A., the FDA determines what drugs are safe for over-the-counter sale; its view is that there is no real concern about the safety of homeopathic remedies because of the extremely small dosages, and the vast majority are over-the-counter drugs that do not need a doctor's prescription. In the U.S.A., homeopathic remedies must have at least one indication for usage for a disease or condition that is self-limiting and that does not require medical diagnosis or medical monitoring.

The European Union allows homeopathic remedies to be sold over-the-counter (provided they are prepared according to the European Pharmacopoeia or the pharmacopoeias currently used officially in the Member States, and if they are at least 3X.), but no specific therapeutic indication may be given on the product label.

Some physicians maintain that homeopathic treatment is relatively unsafe, because it might delay other treatment/s, if it fails to work. Homeopaths respond by claiming that using remedies can delay or reduce the use of conventional medicines that are ineffective and dangerous. The concern is that people who use homeopathy as an alternative to medical care take additional risk when they forego conventional treatment for serious illness (such as anti-inflammatories and bronchodilators for asthma), or do not receive established preventive treatments (such as vaccines or anti-malarial drugs). Homeopaths assert that patients face greater risk in using conventional medicines as a first method of treatment, and remind patients and physicians of the Hippocratic aphorism "First, do no harm."

Probably every modern pharmacologist would agree with Hahnemann that most drugs of the 19th century were at best ineffective and often dangerous. However, some homeopaths question whether modern medicines are safe and effective, and recommend homeopathic remedies instead.

Many homeopaths think that vaccination for common diseases, such as measles, is unnecessary, and that vaccines can be damaging to health, because of the mercury and aluminum in them, because the bacterium or virus in the vaccine may neither be dead nor weak enough, and/or because some childhood infectious diseases may strengthen immune responsiveness. Such advice is considered irresponsible by public health professionals, who assess the benefits of vaccination as vastly outweighing the risks. Measles is not a major killer in the western world, where most children are vaccinated at about two years old, but in 1999 there were 875,000 deaths from measles worldwide, mostly in Africa. In 2001, a "Measles Initiative" was initiated involving the American Red Cross, UNICEF and the World Health Organization, By 2005 more than 360 million children had been vaccinated, and the death toll had dropped to 345,000.

Homeopaths discourage the public from using homeopathic high potency remedies (the 200th potency and higher) unless prescribed by someone adequately trained in homeopathy. They advise that repeated doses of high potency remedies can lead the person to experience a "drug proving," with symptoms akin to an overdose (the symptoms are said to disappear shortly after stopping taking the remedy).

Regulation of homeopathy

There are no universal standards for homeopathic education, but some countries allow homeopaths to describe themselves in equivalent ways to doctors, with a system of qualification and oversight. In some countries, all (or virtually all) professionals that prescribe homeopathic remedies are MDs (such as France, Spain, Argentina, Colombia). Some countries have exclusively homeopathic medical schools (India, Pakistan, Mexico etc.), some have naturopathic medicine colleges in which students are taught homeopathy as part of their curriculum (Germany has its "heilpraktica"/health practitioners; the U.S.A., Canada, and Australia have naturopathic medicine schools that include homeopathy), and some countries certify "professional homeopaths" who have attended homeopathic schools and who then pass independent examinations that grant "certification" as homeopaths. In the U.S.A., there is also a separate certification process available only to MDs and DOs (there are similar choices of certification available in the U.K. for medical doctors, who've done at least MBBS). Also in the U.S.A., naturopathic physicians have their own homeopathic certifying agency.To join the American Institute of Homeopathy today, one must have a mainstream medical license (MD, DO, DDS), as well as homeopathic training.

In India, homeopathy has more than 200,000 registered practitioners and is one of the Indian "National Systems of Medicine" under the Department of AYUSH (Ayurveda, Yoga and Naturopathy, Unani, Siddha and Homeopathy). Every Indian primary health care centre (PHC) has one or more conventional medical doctors and a doctor from the Department of AYUSH. About 10% of the Indian population, over 100 million people, depend solely on homeopathy for their health care needs. In India, it is illegal to practice as a homeopath without a license and professional qualifications.

In the UK, anyone can declare themselves to be a homeopath and practice without any qualification ("common law" allows freedom of choice in medical care there) The great majority of homeopaths are not medically-trained, and many of these belong to the Society of Homeopaths, a European-wide organisation. The Society produces a register of professionally trained and insured homeopaths, who agree to abide by the Society's Code of Ethics and Practice. However, unlike other major CAM professions, homeopathy still has no statutory regulation process. Some statutory regulations apply to non-medically-qualified alternative medicine practitioners: for example, the 1939 Cancer Act makes it illegal to claim to have an effective treatment for cancer if it isn't actually an effective treatment for cancer, and this is enforced by the Trading Standards Office. Beyond that, the same regulations apply to alternative medicine practitioners as to any other commercial operation - such as the Sale of Goods Act, and the Advertising Standards Authority. The advertising code in the U.K. requires that advertisments for homeopathy must include the instruction to "to consult a doctor if symptoms persist".

In the UK, the Faculty of Homeopathy regulates qualified medical professionals who practice homeopathy. It awards accreditations based on medical qualifications - so a doctor would be given an MFHom, and they have others for nurses, pharmacists and vets. The Faculty publishes the journal Homeopathy, and is a founding member of the 'European Committee for Homeopathy', which has developed a European code of professional conduct.Of 248,000 registered practitioners of medicine in the U.K., about 400 are members of the Faculty. Homepaths with medical qualifications have, on occasion, been disciplined by the General Medical Council for using homepathic remedies inappropriately but not by the Faculty, which has no means of enforcing its code of conduct.

In France and Denmark, licenses are required to diagnose any illness or to dispense any product whose purpose is to treat illness.