Homeopathy is a system of medicine introduced by Samuel Hahnemann in the late 18th century. It is based on the principle that "like cures like," meaning that a substance that causes symptoms in a healthy person can cure similar symptoms in a sick person when given at a very low dose. Homeopathy seeks to match a single highly diluted substance to a person's unique symptoms rather than treating the disease directly. The document provides background on the origins and key principles of homeopathy, including how Hahnemann discovered it through experimenting with dilute doses of substances on himself and others.