Alternative medicine describes any practice that aims to achieve the healing effects of medicine, but which lacks biological plausibility and is untested or untestable. In some cases AM treatments are proven ineffective. Complementary medicine (CM), complementary and alternative medicine (CAM), integrated medicine or integrative medicine (IM), and holistic medicine are among many rebrandings of the same phenomenon. Alternative therapies share in common that they reside outside medical science, and rely on pseudoscience. Alternative medicine is distinct from experimental medicine, which employs the scientific method to test plausible therapies by way of responsible and ethical clinical trials, producing evidence of either effect or of no effect. Research into alternative treatments often fails to follow proper research protocol and denies calculalaton of prior probability, providing invalid results. Traditional practices become 'alternative' when used outside their original settings without proper scientific explanation and evidence. Frequently used derogatory terms for the alternative are new-age or pseudo, with little distinction from quackery. In some cases, the claims of alternative practices violate laws of nature; in others, the practice is plausibly effective but so dangerous to the patient that any use is unethical. Alternative practices often resort to the supernatural or superstitious to explain their effect, and range from ineffective to harmful and toxic (e.g. cyanide poisoning from amygdalin, or the intentional ingestion of hydrogen peroxide). Much of the perceived effect of an alternative practice arises from a belief that it will be effective (the placebo effect), or from the treated condition resolving on its own (the natural course of disease). This is further exacerbated by the tendency to turn to alternative treatments upon the failure of medicine, at which point the condition will be at its worst and most likely to spontaneously improve. In the absence of this bias, especially for diseases that are not expected to get better by themselves such as cancer or HIV infection, multiple studies have shown significantly worse outcomes if patients turn to alternative therapies. While this may be because these patients avoid effective treatment, some alternative treatments actively interfere with effective ones. The alternative sector is a highly profitable industry with a strong lobby, and faces far less regulation over the use and marketing of unproven treatments. Its marketing often advertises the treatments as being 'natural' or 'holistic', in comparison to those offered by 'big pharma'. Billions of dollars have been spent studying alternative medicine, with little to no positive results. Some of the successful practices are only considered alternative under very specific definitions, such as those which include all physical activity under the umbrella of 'alternative medicine'. The terms alternative medicine, complementary medicine, integrative medicine, holistic medicine, natural medicine, unorthodox medicine, fringe medicine, unconventional medicine, and new age medicine are used interchangeably as having the same meaning, and are almost synonymous in most contexts. Terminology has shifted over time, reflecting the preferred branding of practitioners. For example, the United States National Institutes of Health department studying alternative medicine, currently named the National Center for Complementary and Integrative Health (NCCIH), was established as the Office of Alternative Medicine (OAM) and was renamed the National Center for Complementary and Alternative Medicine (NCCAM) before obtaining its current name. Therapies are often framed as 'natural' or 'holistic', implicitly and intentionally suggesting that conventional medicine is 'artificial' and 'narrow in scope'. The meaning of the term 'alternative' in the expression 'alternative medicine', is not that it is an effective alternative to medical science, although some alternative medicine promoters may use the loose terminology to give the appearance of effectiveness. Loose terminology may also be used to suggest meaning that a dichotomy exists when it does not, e.g., the use of the expressions 'Western medicine' and 'Eastern medicine' to suggest that the difference is a cultural difference between the Asiatic east and the European west, rather than that the difference is between evidence-based medicine and treatments that do not work. Alternative medicine is defined loosely as a set of products, practices, and theories that are believed or perceived by their users to have the healing effects of medicine, but whose effectiveness has not been established using scientific methods, or whose theory and practice is not part of biomedicine, or whose theories or practices are directly contradicted by scientific evidence or scientific principles used in biomedicine. 'Biomedicine' or 'medicine' is that part of medical science that applies principles of biology, physiology, molecular biology, biophysics, and other natural sciences to clinical practice, using scientific methods to establish the effectiveness of that practice. Unlike medicine, an alternative product or practice does not originate from using scientific methods, but may instead be based on hearsay, religion, tradition, superstition, belief in supernatural energies, pseudoscience, errors in reasoning, propaganda, fraud, or other unscientific sources. Some other definitions seek to specify alternative medicine in terms of its social and political marginality to mainstream healthcare. This can refer to the lack of support that alternative therapies receive from medical scientists regarding access to research funding, sympathetic coverage in the medical press, or inclusion in the standard medical curriculum. For example, a widely used definition devised by the US NCCIH calls it 'a group of diverse medical and health care systems, practices, and products that are not generally considered part of conventional medicine'. However, these descriptive definitions are inadequate in the present-day when some conventional doctors offer alternative medical treatments and introductory courses or modules can be offered as part of standard undergraduate medical training; alternative medicine is taught in more than half of US medical schools and US health insurers are increasingly willing to provide reimbursement for alternative therapies.