The Betel nut quid, which so many chew and stains their teeth really dark red or blackish,is made with betel leaf which is cultivated in most of South and Southeast Asia. Since it is a creeper, it needs a compatible tree or a long pole for support. The leaves are chewed together in a wrapped package along with the areca nut (which, by association, is often inaccurately called the "betel nut") and mineral slaked lime (calcium hydroxide). Catechu, called Kattha in Hindi, and other flavoring substances and spices might be added. The lime acts to keep the active ingredient in its freebase or alkaline form, thus enabling it to enter the bloodstream via sublingual absorption. The areca nut contains the alkaloid arecoline, which promotes salivation (the saliva is stained red), and is itself a stimulant. This combination, known as a "betel quid", has been used for several thousand years.