Piper betel is a vine of the family Piperaceae, which includes pepper and kava. Betel leaf is mostly consumed in Asia, and elsewhere in the world by some Asian emigrants, such as betel quid or paan, with areca nut and/or tobacco. Arecoline has been shown to have carcinogenic properties in laboratory animals. It is considered to be carcinogenic to humans by the International Agency for Research on Cancer (IARC).
Arecoline is a muscarinic acetylcholine receptor agonist. Betel leaf has psychotropic effects due to its chemical components, including arecoline and nicotine, which act as stimulants upon human consumption. Areca is a flowering plant in the palm family Arecaceae, which includes about 50 species from Southeast Asia and Australasia.
The chewing of betel quid or paan originated in South East Asia and came to Indian, Southeast Asian, and Pacific Island countries around 2,000 years ago from India. The leaves from this plant are combined with things such as slaked lime (calcium hydroxide), betel nut (Areca catechu), and/or tobacco. Betel leaf is a common item of consumption throughout the Indian subcontinent and South-East Asia.
Areca is sometimes called betel nut, though this term usually refers to the seeds of the Areca palm rather than the plant itself. "Betel" (or "paan") prepared using these ingredients is often chewed for their stimulating effect and flavor. Betel quid without tobacco is widely used as a mild stimulant in many parts of Asia and is often considered to have psychoactive properties.
Paan masala contains areca nut, betel leaf, and various sweeteners and chutneys. Some South Indian versions include katha paste or "karupatti". It is chewed for its effects as a euphoriant and is spat out, leaving red spit on the ground.
Paan chewing is practiced in some Indian states such as Assam and Tripura, where it is known as "pan", as well as Bangladesh and Pakistan where paan is eaten as a snack. In some parts of India, people also spit betel quid after chewing it, resulting in red spittle stains. This is considered harmless and mostly ignored.
"Paan" is wrapped inside the leaf of a certain variety of palm ("Areca catechu", also known as "Pinang") with slaked lime, which acts as the binding agent, to produce what is commonly known as "pan masala" or "supari". The "supari" is commonly chewed raw, though it may be pan-fried in some communities. Tobacco (often combined with betel leaves) is also frequently added to the mixture.