Alternative medicine or fringe medicine consists of practices claimed to have the healing effects of medicine but which are disproven, unproven, impossible to prove, or are excessively harmful in relation to their effect; and where the scientific consensus is that the therapy does not, or cannot, work because the known laws of nature are violated by its basic claims; or where it is considered so much worse than conventional treatment that it would be unethical to offer as treatment. Alternative therapies or diagnoses are not part of medicine or science-based healthcare systems. Alternative medicine consists of a wide variety of practices, products, and therapies – ranging from those that are biologically plausible but not well tested, to those with known harmful and toxic effects. Contrary to popular belief, significant expense is paid to test alternative medicine, including over US$2.5 billion spent by the United States government. Almost none show any effect beyond that of false treatment. Perceived effects of alternative medicine may be caused by placebo; decreased effect of functional treatment (and therefore potentially decreased side effects); and regression toward the mean where improvement that would have occurred anyway is credited to alternative therapies; or any combination of the above. Alternative treatments are not the same as experimental medicine or traditional medicine, although much of the latter is alternative when used today.