The term Butterfly effect is a concept invented by the American meteorologist, Edward Lorenz to highlight the possibility of small changes causing momentous effects. In simple terms it was used in chaos theory to describe how small changes to unrelated things or conditions could affect large complex systems. This term is derived from a suggestion, that the flapping of the wings of a butterfly in South America could affect the weather in Texas showing that the tiniest influence on a single part of a system could have an impact on another part. This term is used because its wings though fragile do not stir much air as they flap but its minute movement does initiate a series of changes which grow eventually causing a large storm thousands of miles away. The butterfly effect occurs when small event have an exceeding far reaching and a large impact. It implies that large events may be connected to small or even to the minuscule occurrences.

In homeopathy, for example, what appears to be a slight or even insignificant substance – the homeopathic potentised remedy – can have far reaching effects when administered to a human being or other organism.