Homeopathy also homœopathy or homoeopathy; is a form of alternative medicine first defined by Samuel Hahnemann in the 18th century.
Homeopathic practitioners maintain that an ill person can be treated using a substance that can produce, in a healthy person, symptoms similar to those of the illness.
According to homeopaths, serial dilution, with shaking between each dilution, removes the toxic effects of the "remedy"
while the qualities of the substance are retained by the diluent (water, sugar, or alcohol).
The end product is often so diluted that it is indistinguishable from pure water, sugar or alcohol.
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.
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 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 drugs 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.