by EBSCO CAM Review Board

Note : For information on homeopathic treatments for specific conditions, see Homeopathic Treatments by Condition. For information on specific homeopathic remedies, see the Homeopathic Remedies.

What Is Homeopathy?

Homeopathy is an alternative philosophy that believes highly diluted substances have the ability to stimulate the body to heal itself. It is largely based on the following core homeopathic beliefs:

  • A substance that produces a certain set of symptoms in a healthy person has the power to cure a sick person manifesting those same symptoms. In homeopathic medicine this is called Law of Similars, or like cures like.
  • Diluting a remedy makes it more powerful. In homeopathic medicine this is called Law of Infinitesimals.
  • A homeopathic treatment is designed to facilitate a release of the illness. Allopathic treatments (traditional medicine), according to homeopathic beliefs, supresses the symptoms and drives the illness back into the body.

The following is an example of the beliefs: the substance ipecac causes vomiting. According to the first and second laws of homeopathy, significantly diluted ipecac would potentially treat vomiting. The more ipecac was diluted, the more effective it would become.

In the US, homeopathic products are available without a prescription from health food stores, some pharmacies, and the internet to treat symptoms that would otherwis fade on their own with time. The Food and Drug Administration (FDA) has not evaluated these products for effectiveness or safety, but it does require that companies follow strict regulation when making the products.16 Although it may start with similar substances as those used in other alternative treatments like herbal medicines, homeopathy's dilution and selection of substances is unique. Traditional homeopathy actually considers herbal medicine to be similar to traditional medicine in worsening illnesses rather than treating them.

Over the past few decades, a large number of studies investigating the effectiveness of homeopathy have been published. Despite the occasional favorable result, there is no meaningful evidence that homeopathic remedies are effective for any condition.

The Practice of Homeopathy: Constitutional Homeopathy vs. Disease-Oriented Homeopathy

Constitutional (or classical) homeopathy follow traditional homeopathy philosophy. Constitutional homeopaths choose a product based on the symptom picture or pattern of a person, including psychological, emotional, physical, and hereditary factors. A simplified form of homeopathy called disease-oriented (or symptomatic) homeopathy has also been developed. In this form, the remedies are matched with specific diagnosed diseases.

Both types of homeopathy have been studied scientifically, although disease-oriented homeopathy has received more attention for the simple reason that it is easier to study. Neither method has been proven effective.

Homeopathic Dilutions

As mentioned above, homeopathy requires that a chosen mineral, plant, or animal substance be significantly diluted in a solution to create a homeopathic product. The products used in the dilution and the creation process are outlined in Homoeopathic Pharmacopoeia of the United States (HPUS). The FDA requires companies to follow these guidelines to sell products. The HPUS was developed by the carefully recorded observation of symptoms caused by the included natural products.

A small amount of the mineral, plant, or animal product is added to a dilution material, such as alcohol. This combination is then added to more dilution material. These steps are repeated until the desired dilution (or potency) of 6c, 12c, or 30c is reached. These products are so dilute that little or none of the original substance is left. According to principles of homeopathy, each dilution makes the product stronger. The process is called potentization. Sometimes homeopathic products are made with substances that are insoluble. In this case, they are ground up, mixed with lactose, and then made into a homeopathic product. Homeopathic products may be delivered within small white lactose pills, in liquids, or creams that are used externally.

In addition to standard homeopathic solutions that use unrelated substances that happen to produce a similar symptom, there are two forms of homeopathic solutions that use substances specifically related to the condition:

  • Isopathic products are made from the actual substance that causes the condition. For example, a homeopath may use a remedy prepared from cat dander to treat cat allergy.
  • Nosodes are made from infected animal tissues or bodily secretions. Here, a homeopath may dilute ground up, tuberculosis-infected glands from a cow to create a homeopathic product for human tuberculosis.

Nosode homeopathic products are sometimes compared to vaccinations. Superficially, the theory of homeopathy may sound similar to vaccination where the introduction of an altered virus is used to decrease the risk of an infection by the same virus. However, this comparison is inaccurate and misleading. Unlike homeopathic products, vaccinations contain measurable amounts of substances that produce measurable stimulation of the immune system. The benefits of vaccinations are also backed up by an overwhelming amount of research, unlike nosodes.

Scientific Evaluation of Homeopathy

Despite its widespread use in some countries, virtually no scientific authority takes homeopathy seriously. There are several reasons for this intense skepticism, but the most important focuses on a basic fact of chemistry. Simply put, there is nothing material left in a “high-potency” homeopathic product; some force of nature unknown to modern science would have to be involved for homeopathy to work.

Here is why. In the process of making a 30c homeopathic product, the original substance is diluted by a factor of one part in 1030. This is such an enormous dilution that none of the substance could possibly remain. The so-called “highest potency” homeopathic products, therefore, contain no active ingredients. Low potency remedies (6s, 12c) do contain a measurable amount of substance, but these remedies are supposedly less effective than the high potency forms. It goes against basic chemistry principles that a solution with no product is stronger than a solution with a small amount of the product.

Some researchers have speculated that homeopathic products cause subtle alterations in the structure of the fluid in which they are dissolved.3 However, studies with highly sensitive equipment, have failed to find any evidence of such structural changes.10,13 Again, basic principles of chemistry also make it impossible that liquids could retain any changes of the type hypothesized.

There are other practical problems with homeopathy as well. For one, there is no reason to believe that a substance that produces certain symptoms when taken as a whole should cure a disease that just coincidentally happens to possess the same symptoms when it is taken in diluted form. This hypothesis appears too tidy and perfect to truly reflect the messy world of human illness.

Furthermore, the detailed symptom pictures upon which constitutional homeopathy are based are far too specific and personal to offer any likelihood of universal truth. For example, the homeopathic remedy sulphur is said to be useful for people who have red lips, stooped posture, and a tendency toward untidiness in personal affairs. A small selection of other supposed characteristics of this remedy include mid-morning hunger and a tendency for increased discomfort of whatever physical symptoms they may be experiencing between 10:00 and 11:00 a.m. and after exposure to cold air or motion.

For a long time, medical progress was based on carefully recorded observations similar to those that were used to develop and justify homeopathy. However, studies based on observation alone can allow biases of researchers and participants to affect the outcomes. For example, if a particpant expects something to work they may report positive results even if the treatment had no actual effect. We have since learned that other forms of evidence, such as the randomized, double-blind, placebo-controlled trial provide much more reliable results . These trials use protocols like blinding to reduce the risk of participant and researcher bias influencing outcomes, ultimately making results more likely to be true. Peer review is also important for modern research. It is a process where trials go through an assessment from a group of medical peers to help identify flaws and undue influence that affect outcomes. Few of the observations used to define the treatments chosen by homeopaths were performed in this scientifically reliable way.4 The majority of current research on homeopathic treatments, including large, rigorous randomized studies, have failed to find any difference in symptoms or biochemical measures in particpants taking homeopathic products when compared to participants receiving no treatment.5,11,12,14

In 1997, scientists Klaus Linde, Nicola Clausius, and others published a groundbreaking review of all placebo-controlled trials of homeopathic products. This article appeared in a prestigious British journal, The Lancet .6 The authors wanted to determine whether there was enough evidence in total to say that homeopathy has benefits beyond the placebo effect. The results of this meta-analysis were initially positive and have been widely quoted by advocates of homeopathy to conclude that the method has been proven effective. However, not all double-blind, placebo-controlled trials are created equal. Fairly subtle design flaws can invalidate the results of a study that, on first glance, seems rigorous. In 1999 the authors re-analyzed the data and noticed a direct relationship between the quality of the study and the amount of benefit seen: the higher the quality, the less the benefit. 7,8 Based on this, Linde et al. concluded that their original meta-analysis overestimated the extent to which homeopathy had been found more effective than placebo. A 2005 evaluation of all the evidence regarding homeopathy also failed to find convincing evidence that homeopathy is more effective than placebo. 15

Since basic principles of medical science are at odds with the foundational theory of homeopathy, what should be made of the occasional randomized controlled trial that appears to show benefit? Do flaws lie in medical science or with completed research? It is unlikely that homeopathy operates through some mysterious new force that science has failed to discover. It is far more likely that the positive outcomes were the result of flawed trials that produced unreliable results.

What to Expect From a Session With a Homeopathic Physician

To understand how a visit to a homeopathic physician works, consider the following imaginary scenario: Sam has felt tense and nervous for months. His workload has increased dramatically since he started a new job last year. He has not been sleeping well, and he has lost weight. His conventional physician recommends a stress-reduction program consisting of gentle exercise and regular relaxation, but he decides to try classical homeopathy instead.

His initial homeopathic consultation consists of a lengthy interview. The homeopath makes note of small nuances that would not be considered important by a conventional physician. Aside from his nervousness, Sam has been suffering from frequent nosebleeds, easy bruising, dry cough, hoarseness of voice at times, and occasional diarrhea and stomach aches.

The doctor asks whether cold drinks relieve his stomach pain, and Sam nods. Next, the homeopath asks him several questions about his family history, personality, and psychological tendencies. Sam says that he is outgoing and friendly and likes company. “You wouldn’t happen to be afraid of thunderstorms,” she asks, and Sam answers that, in fact, he is. The interview continues for an hour.

Based on her analysis of Sam’s “constitution” as revealed by close questioning, the homeopath carefully selects a homeopathic remedy that matches, based on the classic description in the Homeopathic Materia Medica . This text reports the symptoms to be expected when taking an overdose of various substances. These descriptions are complex and elaborate, covering physical and psychological symptoms that developed in the people who undertook the experiment; taken together, they represent the “symptom picture” of the remedy.

Sam’s homeopath chooses the remedy Phosphorus , because its symptom picture matches him closely. He is told to take the remedy for 3 months. During the period of treatment, he is advised to avoid the use of any pharmaceutical drugs, medicinal herbs (such as St. John’s wort), or foods with drug-like properties (eg, coffee) because they have properties that might “antidote” (counteract) the effect of treatment. At the end of 3 months, he is advised to call for a follow-up visit, at which point he may be given a new remedy to treat “deeper” problems that may emerge.

Note : This description applies to practitioners using classical or constitutional homeopathy. Many alternative practitioners use homeopathic remedies to treat particular diseases and use herbs and supplements in conjunction with them.

A Note About Safety

Today, conventional medicine is far safer and effective then previous times but most pharmaceutical medications present at least some risk. In principle, this should not be the case with homeopathic treatments. On a chemical basis, there is nothing in them or, for low potency formulations, next to nothing. Although this may true for products manufactured under strict quality controls, potentially toxic substances have been found in some homeopathic products at concentrations high enough to produce adverse effects or allergic reactions.17

In addition, there is always the threat of harm befalling patients who avoid or stop taking proven-effective treatments in favor of homeopathic products, especially for chronic or serious health conditions.17


As we shall see in subsequent pages, some studies have reported positive results. However, rigorous studies have failed to find it effective, and overall, the body of supporting evidence is too weak to overcome the reasonable presumption that it cannot work.

Homeopathic Treatments by Condition

Homeopathy has been used traditionally to treat virtually all conceivable medical problems. However, this database is limited to conditions for which at least one homeopathic remedy has been evaluated in a double-blind, placebo-controlled trial.


REF1 Lockie A. The Family Guide to Homeopathy . Simon and Schuster; 1989.

REF2 Weil A. Health and Healing . Houghton Mifflin Company; 1995.

REF3 Gray B. Homeopathy: Science or Myth . Berkeley, CA: North Atlantic Books; 2000:51-99.

REF4 Dantas F, Fisher P. A systematic review of homeopathic pathogenetic trials (“provings”) published in the United Kingdom from 1945 to 1995. In: Ernst E, ed. Homeopathy: A Critical Appraisal . London: Butterworth Heinemann; 1998:69-97.

REF5 Fisher P, Dantas F. Homeopathic pathogenetic trials of Acidum malicum and Acidum ascorbicum. Br Homeopath J . 2001;90:118-125.

REF6 Linde K, Clausius N, Ramirez G, et al. Are the clinical effects of homeopathy placebo effects? A meta-analysis of placebo-controlled trials. Lancet . 1997;350:834-843.

REF7 Linde K, Scholz M, Ramirez G, et al. Impact of study quality on outcome in placebo-controlled trials of homeopathy. J Clin Epidemiol . 1999;52:631-636.

REF8 Ernst E, Pittler MH. Re-analysis of previous meta-analysis of clinical trials of homeopathy [letter]. J Clin Epidemiol . 2000;53:1188.

REF9 Grabia S, Ernst E. Homeopathic aggravations: a systematic review of randomised, placebo-controlled clinical trials. Homeopathy . 2003;92:92-98.

REF10 Anick DJ. High sensitivity 1H-NMR spectroscopy of homeopathic remedies made in water. BMC Complement Altern Med . 2004 Nov 1. [Epub ahead of print]

REF11 Brien S, Lewith G, Bryant T. Ultramolecular homeopathy has no observable clinical effects. A randomized, double-blind, placebo-controlled proving trial of Belladonna 30C. Br J Clin Pharmacol . 2003;56:562-568.

REF12 Vickers AJ, van Haselen R, Heger M. Can homeopathically prepared mercury cause symptoms in healthy volunteers? A randomized, double-blind placebo-controlled trial. J Altern Complement Med . 2001;7:141-148.

REF13 Walach H, Jonas WB, Ives J, et al. Research on homeopathy: state of the art. J Altern Complement Med . 2005;11:813-829.

REF14 Witt CM, Bluth M, Hinderlich S, et al. Does Potentized HgCl(2) (Mercurius corrosivus) Affect the Activity of Diastase and alpha-Amylase? J Altern Complement Med. 2006;12:359-365.

REF15 Ernst E. Is homeopathy a clinically valuable approach? Trends Pharmacol Sci. 2005 Sept 12. [Epub ahead of print].

REF16 FDA. CPG Sec. 400.400 Conditions Under Which Homeopathic Drugs May be Marketed

REF17 Posadki P, Alotaibi A, Ernst E. Adverse effects of homeopathy: a systematic review of published case reports and case series. International Journal of Clinical Practice 66:1178-1188, 2012.

REF18 National Center for Complementary and Integrative Health. Homeopathy and introduction. Available at: Accessed August 13, 2015.

Revision Information

  • Reviewer: EBSCO CAM Review Board
  • Review Date: 09/2015
  • Update Date: 10/02/2015