Homeopathy: An Introduction
Homeopathy, also known
as homeopathic medicine, is a whole medical system that was developed in Germany more than 200
years ago and has been practiced in the United States since the early 19th century. Homeopathy
is used for wellness and prevention and to treat many diseases and conditions. This fact sheet provides a
general overview of homeopathy and suggests sources for additional information.
- The principle of similars (or "like cures like") is a central homeopathic principle. The principle states
that a disease can be cured by a substance that produces similar symptoms in healthy people.
- Most analyses have concluded that there is little evidence to support homeopathy as an effective treatment
for any specific condition; although, some studies have reported positive findings.
- There are challenges in studying homeopathy and controversies regarding the field, largely because a number
of its key concepts are not consistent with the current understanding of science, particularly chemistry and
- There is limited research on the safety of homeopathic treatments.
- Tell your health care providers about any complementary and alternative practices you use. Give them a full
picture of all you do to manage your health. This will help ensure coordinated and safe care.
The term homeopathy comes from the Greek words homeo, meaning similar, and pathos, meaning suffering or disease.
Homeopathy seeks to stimulate the body's ability to heal itself by giving very small doses of highly diluted
substances. This therapeutic method was developed by German physician Samuel Christian Hahnemann at the end of the
18th century. Hahnemann articulated two main principles:
- The principle of similars (or "like cures like") states that a disease can be cured by a substance that
produces similar symptoms in healthy people. This idea, which can be traced back to Hippocrates, was further
developed by Hahnemann after he repeatedly ingested cinchona bark, a popular treatment for malaria, and found
that he developed the symptoms of the disease. Hahnemann theorized that if a substance could cause disease
symptoms in a healthy person, small amounts could cure a sick person who had similar symptoms.
- The principle of dilutions (or "law of minimum dose") states that the lower the dose of the medication, the
greater its effectiveness. In homeopathy, substances are diluted in a stepwise fashion and shaken vigorously
between each dilution. This process, referred to as "potentization," is believed to transmit some form of
information or energy from the original substance to the final diluted remedy. Most homeopathic remedies are so
dilute that no molecules of the healing substance remain; however, in homeopathy, it is believed that the
substance has left its imprint or "essence," which stimulates the body to heal itself (this theory is called
the "memory of water").
Homeopaths treat people based on genetic and personal health history, body type, and current physical,
emotional, and mental symptoms. Patient visits tend to be lengthy. Treatments are "individualized" or tailored to
each person—it is not uncommon for different people with the same condition to receive different treatments.
Homeopathic remedies are derived from natural substances that come from plants, minerals, or animals. Common
remedies include red onion, arnica (mountain herb), and stinging nettle plant.
Use in the United States
According to the 2007 National Health Interview Survey, which included a comprehensive survey of complementary and alternative medicine (CAM) use by Americans, an
estimated 3.9 million U.S. adults and approximately 900,000 children used homeopathy in the previous year.
People use homeopathy for a range of health concerns, from wellness and prevention, to the treatment of diseases
and conditions such as allergies, asthma, chronic fatigue syndrome, depression, digestive disorders, ear
infections, headaches, and skin rashes.
Regulation of Homeopathic Treatments
Homeopathic remedies are prepared according to the guidelines of the Homeopathic Pharmacopeia of the United States
(HPUS), which was written into law in the Federal Food, Drug, and Cosmetic Act in 1938. Homeopathic remedies are
regulated in the same manner as nonprescription, over-the-counter (OTC) drugs. However, because homeopathic
products contain little or no active ingredients, they do not have to undergo the same safety and efficacy testing
as prescription and new OTC drugs.
The U.S. Food and Drug Administration (FDA) does require that homeopathic remedies meet certain legal standards for
strength, purity, and packaging. The labels on the remedies must include at least one major indication (i.e.,
medical problem to be treated), a list of ingredients, the dilution, and safety instructions. In addition, if a
homeopathic remedy claims to treat a serious disease such as cancer, it needs to be sold by prescription. Only
products for self-limiting conditions (minor health problems like a cold or headache that go away on their own) can
be sold without a prescription.
The Status of Homeopathy Research
Most analyses of the research on homeopathy have concluded that there is little evidence to support homeopathy as
an effective treatment for any specific condition, and that many of the studies have been flawed. However, there
are some individual observational studies, randomized placebo-controlled trials, and laboratory research that
report positive effects or unique physical and chemical properties of homeopathic remedies.
Homeopathy is difficult to study using current scientific methods because highly diluted substances (known as
ultra-high dilutions or UHDs) cannot be readily measured, making it difficult to design or replicate studies. In
addition, homeopathic treatments are highly individualized and there is no uniform prescribing standard for
homeopaths. There are hundreds of different homeopathic remedies, which can be prescribed in a variety of different
dilutions to treat thousands of symptoms. On the other hand, many aspects of the interactions between the
homeopathic practitioner and his or her patients may be quite beneficial, and can be studied more easily.
Controversies Regarding Homeopathy
Homeopathy is a controversial area of CAM because a number of its key concepts are not consistent with established
laws of science (particularly chemistry and physics). Critics think it is implausible that a remedy containing a
miniscule amount of an active ingredient (sometimes not a single molecule of the original compound) can have any
biological effect—beneficial or otherwise. For these reasons, critics argue that continuing the scientific study of
homeopathy is not worthwhile. Others point to observational and anecdotal evidence that homeopathy does work and
argue that it should not be rejected just because science has not been able to explain it.
Side Effects and Risks
Although the side effects and risks of homeopathic treatments are not well researched outside of observational
studies, some general points can be made about the safety of these treatments:
- A systematic review found that homeopathic remedies in high dilution, taken under the supervision of
trained professionals, are generally considered safe and unlikely to cause severe adverse reactions.
- Liquid homeopathic remedies may contain alcohol. The FDA allows higher levels of alcohol in these remedies
than it allows in conventional drugs. However, no adverse effects from alcohol levels have been reported to the
- Homeopaths expect some of their patients to experience homeopathic aggravation (a temporary worsening of
existing symptoms after taking a homeopathic prescription). Researchers have not found much evidence of this
reaction in clinical studies; however, research on homeopathic aggravations is scarce.
- Homeopathic remedies are not known to interfere with conventional drugs; however, if you are considering
using homeopathic remedies, you should discuss this with your health care provider first.
Licensing and Certification
There are currently no uniform licensing or professional standards for the practice of homeopathy in the United
States; the licensing of homeopaths varies from state to state. Usually, a homeopathic practitioner is licensed in
a medical profession, such as conventional or osteopathic medicine. Homeopathy is also part of the medical
education for naturopathy.
Licensure as a homeopathic physician is available only to medical doctors and doctors of osteopathy in Arizona,
Connecticut, and Nevada. Arizona and Nevada also license homeopathic assistants, who are allowed to perform medical
services under the supervision of a homeopathic physician. Some states explicitly include homeopathy within the
scope of practice of chiropractic, naturopathy, physical therapy, dentistry, nursing, and veterinary medicine.
National certification may be obtained through organizations such as the Council for Homeopathic Certification,
American Board of Homeotherapeutics, and the Homeopathic Academy of Naturopathic Physicians. The U.S. Department of
Education, which officially recognizes some CAM organizations for certification purposes, has not recognized these
organizations; however, members of the homeopathic community consider certification a way to help set education and
competency standards for practicing homeopathy.
If You Are Thinking About Using Homeopathy
- Do not use homeopathy as a replacement for proven conventional care or to postpone seeing a doctor about a
- Look for published research studies on homeopathy for the health condition you are interested in.
- If you are considering using homeopathy and decide to seek treatment from a homeopath, ask about the
training and experience of the practitioner you are considering.
- Women who are pregnant or nursing, or people who are thinking of using homeopathy to treat a child, should
consult their health care provider.
- Tell your health care providers about any complementary and alternative practices you use. Give them a full
picture of all you do to manage your health. This will ensure coordinated and safe care. For tips about talking
with your health care providers about CAM, see NCCAM's Time to Talk campaign.
NCCAM-supported exploratory grants have sought to understand patient and provider perspectives on homeopathic
treatment and have explored the effectiveness of homeopathic remedies with various succussions (vigorous shaking)
- Ballard R.
Homeopathy: an overview. Australian Family
- Cucherat M, Haugh MC, Gooch M, et
Evidence of clinical efficacy of homeopathy: a meta-analysis of
clinical trials. European Journal of Clinical Pharmacology.
- Dantas F, Rampes H.
Do homeopathic medicines provoke adverse effects? A systematic
review. British Homeopathic Journal. 2000;89(Suppl
- Der Marderosian AH.
Understanding homeopathy. Journal of the American
- Eisenberg DM, Cohen MH, Hrbek A, et
Credentialing complementary and alternative medical
providers. Annals of Internal Medicine.
- Ernst E.
A systematic review of systematic reviews of
homeopathy. British Journal of Clinical Pharmacology.
- Ernst E.
The truth about homeopathy. British Journal of Clinical
- Ernst E, Kaptchuk TJ.
Homeopathy revisited. Archives of Internal
- Homeopathy. Natural Standard Database Web
site. Accessed on January 29, 2009.
- Jonas WB, Kaptchuk TJ, and Linde
A critical overview of
homeopathy. Annals of Internal Medicine.
- Linde K, Clausius N, Ramirez G, et
Are the clinical effects of homeopathy placebo effects? A
meta-analysis of placebo-controlled trials. Lancet. 1997;350(9081):834–843.
- Merrell WC, Shalts E.
Homeopathy . Medical Clinics of
I. Homeopathy: real medicine or
empty promises? FDA Consumer. 1996;30(10):15–19.
- Tedesco P, Cicchetti J.
Like cures like: homeopathy. American Journal of
- U.S. Food and Drug Administration. Conditions under which homeopathic drugs may be
marketed. Compliance Policy Guides
Manual, Sec. 400.400. U.S. Food and Drug Administration Web
site. Accessed at http://www.fda.gov/ora/compliance_ref/cpg/cpgdrg/cpg400-400.html
on May 29,
- Vallance, A.K.
Can biological activity be maintained at ultra-high dilution? An
overview of homeopathy, evidence, and Bayesian philosophy. Journal of Alternative and Complementary