Turmeric is a flowering plant of the ginger family, Zingiberaceae, the roots of which are used in cooking. The plant is rhizomatous, herbaceous, and perennial, and is native to the Indian subcontinent and Southeast Asia, and requires temperatures between 20 and 30 °C (68 and 86 °F) and a considerable amount of annual rainfall to thrive. Plants are gathered each year for their rhizomes, some for propagation in the following season and some for consumption.
When not used fresh, the rhizomes are boiled in water 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 many Asian cuisines, especially for curries, as well as for dyeing. Turmeric powder has a warm, bitter, black pepper-like flavor and earthy, mustard-like aroma.
Although long used in Ayurvedic medicine, where it is also known as haridra, no high-quality clinical evidence exists for use of turmeric or its constituent, curcumin, as a therapy.