Turmeric is a rhizomatous herbaceous perennial plant (Curcuma longa) of the ginger family, Zingiberaceae. It is native to southern Asia, requiring temperatures between 20 and 30 °C (68 and 86 °F) and a considerable amount of annual rainfall to thrive. Plants are gathered annually for their rhizomes and propagated from some of those rhizomes in the following season.
When not used fresh, the rhizomes are boiled for about 30–45 minutes and then dried in hot ovens, after which they are ground into a deep-orange-yellow powder commonly used as a coloring and flavoring agent in the cuisines of Bangladesh, India, Indonesia, Iran and Pakistani cuisine, especially for curries, as well as for dyeing.
Although long-used in Ayurvedic medicine to treat various diseases, there is little high-quality clinical evidence for use of turmeric or its main constituent, curcumin, as a therapy.