Homeopathy or homoeopathy is a pseudoscientific system of alternative medicine. Its practitioners, called homeopaths, believe that a substance that causes symptoms of a disease in healthy people can cure similar symptoms in sick people; this doctrine is called similia similibus curentur, or “like cures like”. All relevant scientific knowledge about physics, chemistry, biochemistry and biology contradicts homeopathy. Homeopathic remedies are typically biochemically inert, and have no effect on any known disease.Its theory of disease, centered around principles Hahnemann termed miasms, is inconsistent with subsequent identification of viruses and bacteria as causes of disease.