Homeopathy is an alternative system of medicine founded in the 1790s by Samuel Hahnemann, based on two principles: “like cures like” — a substance causing symptoms in health treats those symptoms in illness — and extreme dilution, where repeated diluting and shaking supposedly potentises the remedy. The resulting preparations typically contain no molecules of the original substance. Homeopathy remains popular worldwide, with devoted users reporting benefit — though controlled trials consistently show effects indistinguishable from placebo, and its proposed mechanisms contradict established physics and chemistry. Medical authorities advise that while homeopathy itself is low-risk, relying on it instead of effective treatment for serious conditions — infections, cancer, diabetes — can cause real harm through delay.