Homeopathy or homoeopathy—from the Greek hómoios (similar) and páthos (suffering)—is a system of Alternative medicine based on the idea that substances known to cause particular combinations of symptoms in healthy people can also, in low and specially prepared doses, help to cure people whose disease has similar symptoms.
The underlying concept of homeopathy is "like cures like" and is based on "the principle of similars", which asserts that substances known to cause particular symptoms can also, in low and specially prepared doses, help to cure diseases that cause similar symptoms, thus its derived name from the Greek hómoios (similar) and páthos (suffering). Remedies are prepared by a well defined process, which includes a trituration of the oroginal substance in lactose and following in their diluting into extremely small doses, while vigorously shaking them ("succussing") with each step of diluting in water or ethanol. They are then dispensed in pills, globules or liquid form. According to the homeopathic method this dilution and succussion process is what gives the remedies their potency.
Some principles of homeopathy have been utilized in various forms in various medical systems for thousands of years in many diverse cultures, but they were first methodically set out by a German physician, Samuel Hahnemann (1755–1843), who observed that a medicine sometimes evoked symptoms similar to those of the illness for which it was prescribed.