Indole-3-acetic acid, also known as IAA, is a heterocyclic compound that is a phytohormone called auxin. This colourless solid is native plant compound, potent and the most important auxin. The molecule is derived from indole, containing a carboxymethyl group (acetic acid). Auxins play a key role in coordination of many growth and behavioral processes in the plant's life cycle and are essential for plant body development.