The castor bean, which, despite its name, is not a true bean. Castor is indigenous to the southeastern Mediterranean Basin, Eastern Africa, and India, but is widespread throughout tropical regions.Castor seed is the source of castor oil, which has a wide variety of uses.
• Castor oil is produced by pressing ripe seeds that have had their outer covering (hull) removed. Castor oil has been used as medicine for centuries.
• Castor seeds without the hull are used for birth control, constipation, leprosy, and syphilis.
• Ricin from the hull of the castor seed has been tested as a chemical warfare agent.