Indole-3-acetic acid, also known as IAA, is a heterocyclic compound that is an phytohormones called auxins. This colourless solid is probably the most important plant auxin. The molecule is derived from indole, containing a carboxymethyl group (acetic acid). IAA has many different effects, as all auxins do, such as inducing cell elongation and cell division with all subsequent results for plant growth and development. There are less expensive and metabolically stable synthetic auxin analogs on the market for use in horticulture, such as indole-3-butyric acid (IBA) and 1-naphthaleneacetic acid (NAA).