Alternative medicine or fringe medicine are practices claimed to have the healing effects of medicine but are disproven, unproven, impossible to prove, or only harmful. 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. Alternative medicine practices may be classified by their cultural origins or by the types of beliefs upon which they are based. Methods may incorporate or be based on traditional medicinal practices of a particular culture, folk knowledge, supersition, spiritual beliefs, belief in supernatural energies (antiscience), pseudoscience, errors in reasoning, propaganda, fraud, new or different concepts of health and disease, and any bases other than being proven by scientific methods.