a purgative, and self-medication or any use without medical supervision is strongly advised against in Ayurvedic texts. Though it has been used in herbalism for millennia, little research has been conducted in modern times, although it is an ingredient in some mass-produced herbal laxatives. When used as such, it is known as "cassia pods". In India, a cathartic made from the pulp is sometimes added to tobacco. A paste of the flowers is used as an ointment for pimples. Culture Cassia fistula is both the national tree and national flower of Thailand – in Thai ratchaphruek (Thai: ราชพฤกษ์) and the blossoms commonly referred to as dok khun (Thai: ดอกคูน). Its yellow flowers symbolize Thai royalty. A 2006–2007 flower festival, the Royal Flora Ratchaphruek, was named after the tree. Cassia fistula is also featured on a 2003 joint Canadian-Thai design for a 48-cent stamp, part of a series featuring national emblems. The Indian laburnum is the state flower of Kerala. The flowers are of ritual importance in the Vishu festival of Kerala. The tree has been depicted on a 20-rupee stamp. The tree is frequently cultivated in Buddhist temples in Sri Lanka where the Sinhala name is Ehela, ඇහැල. In Laos, its blooming flowers known locally as dok khoun are associated with the Lao New Year. People use the flowers as offerings at the temple and also hang them in their homes for the New Year in belief that the flowers will bring happiness and good luck to the households. The laburnum is the school tree of National Taiwan Normal University, thought to be because of the seed pods' similarity to the whips used by teachers in times past. Gallery References External links (2008): Kerala Symbols fistula Flora of tropical Asia Medicinal plants of Asia National symbols of Thailand Plants used in Ayurveda Plants described in 1753 Taxa named by Carl Linnaeus Trees in Buddhism