Betel: Difference between revisions

{{About||the mixture of betel leaf and areca nut|PaanBetel nut chewing|the biblical place|Bethel}}

The '''betelBetel''' ('''''Piper betle''''') is a [[vine]]species of theflowering familyplant [[Piperaceae]],in which includes [[Blackthe pepper|pepper]] andfamily [[kavaPiperaceae]]. The betel plant is, native to [[Southeast Asia]]. It is an evergreen, [[dioecious]]<ref name="RimandoHan1986"/> [[Perennial plant|perennial]]vine, with glossy heart-shaped leaves and white [[catkin]]s. Betel plants are cultivated for their leaves which isare most commonly used as flavoring in chewing [[areca nut]] ([[betel nut chewing]]).

''Piper betle'' is originally native to [[South Asia]] and in [[Southeast Asia]], from [[Island Southeast AsiaIndia]], ([[Philippines]], [[Timor-Leste]] and the [[Lesser Sunda Islands]], and [[Peninsular Malaysia]]) to [[Indochina]], ([[Vietnam]], [[Cambodia]], [[Laos]], [[Thailand]], and [[Myanmar]]). Its cultivation has spread along with the [[Austronesian expansion|Austronesian migrations]] and [[Austronesian maritime trade network|trade]] to other parts of [[Island Southeast Asia]], [[Papua New Guinea]] and [[Melanesia]], [[Micronesia]], [[South Asia]], the [[Maldives]], [[Mauritius]], [[Réunion Island]], and [[Madagascar]]. It has also beenwas introduced during the [[Colonial Era]] to the [[Caribbean]].<ref name="powo">{{cite web |title=''Piper betle'' L. |url=https://powo.science.kew.org/taxon/680605-1 |website=Plants of the World Online |publisher=Royal Botanic Gardens, Kew |access-date=23 April 2022}}</ref><ref name="Zumbroich2007">{{cite journal |last1=Zumbroich |first1=Thomas J. |title=The origin and diffusion of betel chewing: a synthesis of evidence from South Asia, Southeast Asia and beyond |journal=eJournal of Indian Medicine |date=2007–2008 |volume=1 |pages=87–140 |url=https://ugp.rug.nl/eJIM/article/download/24712/22162}}</ref>

The betel leaf is cultivated mostly in South and Southeast Asia, from [[PakistanIndia]]<ref>{{cite news|title=Betel-leaf farming in coastal area|url=http://www.dawn.com/news/33381/betel-leaf-farming-in-coastal-area|access-date=30 October 2014|work=[[Dawn (newspaper)|Dawn]]|date=13 May 2002}}</ref> to [[Papua New Guinea]].<ref>{{cite news|last1=Cassey|first1=Brian|title=Chewing over a betel ban|url=http://www.smh.com.au/world/chewing-over-a-betel-ban-20131108-2x6ra.html|access-date=30 October 2014|work=Sydney Morning Herald|date=9 November 2013}}</ref> It needs a compatible tree or a long pole for support. Betel requires well-drained fertile soil. Waterlogged, [[Soil salinity|saline]] and [[alkali soil]]s are unsuitable for its cultivation.<ref name=LK/>

In [[Bangladesh]], farmers called ''barui''<ref name="barouj">{{cite book |last=Karim |first=ASM Enayet |year=2012 |chapter=Pan1 |chapter-url=http://en.banglapedia.org/index.php?title=Pan1 |editor1-last=Islam |editor1-first=Sirajul |editor1-link=Sirajul Islam |editor2-last=Jamal |editor2-first=Ahmed A |title=Banglapedia: National Encyclopedia of Bangladesh |edition=Second |publisher=[[Asiatic Society of Bangladesh]]}}</ref> prepare a garden called a ''barouj'' in which to grow betel. The ''barouj'' is fenced with [[bamboo]] sticks and [[coconut]] leaves. The soil is plowed into furrows of 10 to 15&nbsp;m length, 75&nbsp;cm in width and 75&nbsp;cm depth. [[Press cake|Oil cakes]], [[manure]], and leaves are thoroughly incorporated with the [[topsoil]] of the furrows and [[wood ash]]. The cuttings are planted at the beginning of the [[monsoon]] season.

==Cultural significance and health effects==

{{Main|PaanBetel nut chewing}}

The primary use of betel leaf is as a wrapper for the [[paan|chewing]] of [[areca nut]], (or in modern times, [[tobacco]]), where it is mainly used to add flavour. The practice originated in the [[Philippines]] around 50005,000 years ago, (where the oldest remains of areca nuts and [[Lime (material)|limecalcium]] from crushed sea shells have been found in the [[Duyong Cave]] archaeological site). It was spread along with the [[Austronesian Expansion|Austronesian migrations]] to the rest of [[Southeast Asia]], [[Taiwan]], [[South China]], and [[South Asia]]. However, itIt is unknown when or why betel leaves were first combined with areca nuts, since areca nuts can be chewed alone.<ref name="Zumbroich2007">{{cite journal |last1=Zumbroich |first1=Thomas J. |title=The origin and diffusion of betel chewing: a synthesis of evidence from South Asia, Southeast Asia and beyond |journal=eJournal of Indian Medicine |date=2007–2008 |volume=1 |pages=87–140 |url=https://ugp.rug.nl/eJIM/article/download/24712/22162}}</ref>

While the practice of chewing Betel leaf existed even before the [[common era]], with attested references from at least the 3rd century CE, the ingredient mix (paan/ betel quid) it was chewed with changed over time.<ref name="scripta_mode_history">{{cite journal |doi=10.30674/scripta.67450 |title=Modes of betel leaf consumption in early India. |year=2015 |last1=Gutierrez |first1=Andrea |journal=Scripta Instituti Donneriani Aboensis |url=https://journal.fi/scripta/article/view/67450/27747 |volume=26 |pages=114–34|doi-access=free }}</ref> [[Areca nut]], [[SlakedCalcium lime|mineral slaked limehydroxide]] and [[catechu]] were the historic ingredients, as referenced in texts from 9th century CE,. and tobaccoTobacco started to feature in the 20th century.<ref name="scripta_mode_history"/><ref name="sa_cancer">{{cite journal |doi=10.4103/2278-330X.114120 |title=Betel leaf: Revisiting the benefits of an ancient Indian herb |year=2013 |last1=Toprani |first1=Rajendra |last2=Patel |first2=Daxesh |journal=South Asian Journal of Cancer |volume=2 |issue=3 |pages=140–141|pmid=24455591 |pmc=3892533 |doi-access=free }}</ref> The practice of chewing betel leaf is on the decline, and now the quid consisting of tobacco, areca nut, and slaked[[limewater]], limeknown as ([[gutka]]), is more popular.<ref name="sa_cancer"/>

In [[India]] and [[Sri Lanka]], a sheaf of betel leaves is traditionally offered as a mark of respect and auspicious beginnings in traditional Indian culture. Occasions include greeting elders at wedding ceremonies, celebrating the New Year, and offering payment to physicians and astrologers, (to whom money and/or areca nut, placed on top of the sheaf of leaves, are offered in thanks for blessings). In Bengali weddings,the bride is brought to the groom,seated on a platform and her face covered in betel leaves.

In [[Papua New Guinea]] and the [[Solomon Islands]], the fresh[[inflorescence]] fruitstalk of the betel tree, known as ''daka'' or "mustard stick", is also consumed together with the leaves.<ref>{{Cite web|url=https://bicon.agriculture.gov.au/BiconWeb4.0/ImportConditions/Conditions?EvaluatableElementId=505572&Path=UNDEFINED&UserContext=External&EvaluationStateId=c07f9c08-7e77-4e40-922a-69f1723b0f6f&CaseElementPk=1426181&EvaluationPhase=ImportDefinition&HasAlerts=False&HasChangeNotices=False&IsAEP=False|title=BICON - Import Conditions - Conditions|website=bicon.agriculture.gov.au|accessdate=11 March 2023}}</ref><ref>{{Cite web|url=http://coraltriangle.blogs.panda.org/coral-reefs/making-lime-for-betelnut-chewing-in-mbuke-manus-png|title=Making Lime for Betelnut Chewing in M'Buke, Manus, PNG|date=25 July 2010|website=WWF Coral Triangle Blog|accessdate=11 March 2023}}</ref>

Epidemiological studies demonstrate a close association between the incidence of cancer in India and the chewing of betel quid containing tobacco, areca nut, lime and betel leaf.<ref name="tata_eug">{{cite journal |doi=10.1016/0278-6915(86)90065-7 |title=Hydroxychavicol: A new phenolic antimutagen from betel leaf |year=1986 |last1=Amonkar |first1=A.J. |last2=Nagabhushan |first2=M |last3=D'Souza |first3=A.V. |last4=Bhide |first4=S.V. |journal=Food and Chemical Toxicology |url=https://www.sciencedirect.com/science/article/pii/0278691586900657#! |volume=24 |issue=12 |pages=1321–1324|pmid=3100406 }}</ref> Chewing paan (betel quid) is strongly associated with a higher risk of developing [[head and neck cancer]],<ref name="NCIfact">{{cite web |date=29 March 2017 |title=Head and Neck Cancers |url=https://www.cancer.gov/types/head-and-neck/head-neck-fact-sheet |website=[[National Cancer Institute|NCI]] |access-date=7 February 2021}}</ref> as well as [[Oropharyngeal cancer|oropharyngeal squamous cell carcinoma (OPSCC)]], a form of cancer that affects the [[Oropharynx|mouth, tonsils, and throat]].<ref name="StatPearls 2020">{{cite book |last1=A |first1=Fatima |last2=Zohaib |first2=J |title=Definitions |chapter=Oropharyngeal Squamous Cell Carcinoma |date=4 December 2020 |chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK563268/ |work=StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |edition=Updated |id=Bookshelf ID: NBK563268 |doi=10.32388/G6TG1L |pmid=33085415 |s2cid=229252540 |via=[[NCBI]] |access-date=7 February 2021}}</ref> Attempts have been made to confirm the [[carcinogen]]ic/ [[mutagen]]ic of betel quid or its ingredients. Betel leaf extract alone has not been shown to cause adverse effects. Smokeless tobacco products have been shown to exhibit mutagenic and carcinogenic behavior.<ref name="oup">{{cite journal |doi=10.1093/carcin/8.5.741 |title=Mutagenic activity in smokeless tobacco products sold in the USA |year=1987 |last1=Guttenplan |first1=Joseph B. |journal=Carcinogenesis |url=https://academic.oup.com/carcin/article/8/5/741/2478262?login=true |volume=8 |issue=5 |pages=741–743|pmid=3581433 }}</ref><ref>{{cite journal |doi=10.1001/jama.1941.02820190006002 |title=The etiologic role of chewing tobacco in cancer of the mouth: Report of eight cases treated with radiation |year=1941 |last1=Friedell |first1=H.L. |last2=Rosenthal |first2=L.M. |journal=JAMA: The Journal of the American Medical Association |url=https://jamanetwork.com/journals/jama/article-abstract/248673 |volume=116 |issue=19 |pages=2130–2135}}</ref> A scientific study from Japan found that lab rats that ate a mixture of betel leaf and areca nuts had severe thickening of the upper digestive tract, whereas after a diet of betel leaves alone, only one laboratory rat developed a forestomach papilloma.<ref name="DoiBF">{{cite journal |doi=10.1007/BF01964368 |title=Carcinogenicity examination of betel nuts and piper betel leaves |year=1979 |last1=Mori |first1=H. |last2=Matsubara |first2=N. |last3=Ushimaru |first3=Y. |last4=Hirono |first4=I. |journal=Experientia |volume=35 |issue=3 |pages=384–5 |pmid=446629|s2cid=30379485 }}</ref> Multiple studies demonstrate that betel quid without added tobacco also causes esophageal cancer, and in some instances, liver cancer.<ref>{{cite journal |doi=10.1016/S1470-2045(09)70326-2 |title=A review of human carcinogens—Part E: tobacco, areca nut, alcohol, coal smoke, and salted fish |year=2009 |first1=Béatrice |last1=Secretan |first2=Kurt |last2=Straif |first3=Robert |last3=Baan |first4=Yann |last4=Grosse |first5=Fatiha |last5=El Ghissassi |first6=Véronique |last6=Bouvard |first7=Lamia |last7=Benbrahim-Tallaa |first8=Neela |last8=Guha |first9=Crystal |last9=Freeman |first10=Laurent |last10=Galichet |first11=Vincent |last11=Cogliano |journal=The Lancet Oncology |url=https://academic.oup.com/carcin/article/8/5/741/2478262?login=true |volume=10 |issue=11 |pages=1033–1034|pmid=19891056 }}</ref> In a cancer diagnosis patterns study with patients that chewed betel quid with different ingredient combinations, the risk was found to be the highest for those using any form of tobacco.<ref>{{cite journal |doi=10.1054/bjoc.2001.1920 |title=Betel nut and tobacco chewing; potential risk factors of cancer of oesophagus in Assam, India |year=2001 |last1=Phukan |first1=R. K. |last2=Ali |first2=M. S. |last3=Chetia |first3=C. K. |last4=Mahanta |first4=J. |journal=British Journal of Cancer |volume=85 |issue=5 |pages=661–667|pmid=11531248 |pmc=2364125 }}</ref> [[International Agency for Research on Cancer]] (IARC) and the [[World Health Organization]] (WHO) accept the scientific evidence that chewing tobacco and areca nut is [[carcinogenic]] to humans.<ref name=WHOCancer>{{cite book|title=Betel-quid and areca-nut chewing and some areca-nut-derived Nitrosamines|author=IARC Working Group|publisher=The World Health Organization|url=http://monographs.iarc.fr/ENG/Monographs/vol85/mono85.pdf|isbn=9789283215851}}</ref><ref>{{cite book |title=WHO Report on the Global Tobacco Epidemic, 2008: the MPOWER package |year=2008 |publisher=World Health Organization |location=Geneva |isbn=978-92-4-159628-2 |url=https://www.who.int/tobacco/mpower/mpower_report_full_2008.pdf|archive-url=https://web.archive.org/web/20080308173338/http://www.who.int/tobacco/mpower/mpower_report_full_2008.pdf|url-status=dead|archive-date=March 8, 2008}}</ref><ref>{{cite journal |doi=10.1136/bmj.324.7341.799 |title=Areca nut use: An independent risk factor for oral cancer |year=2002 |last1=Warnakulasuriya |first1=S. |journal=BMJ |volume=324 |issue=7341 |pages=799–800 |pmid=11934759 |last2=Trivedy |first2=C |last3=Peters |first3=TJ |pmc=1122751}}</ref><ref>{{cite journal |first1=Bhavana J. |last1=Dave |first2=Amit H. |last2=Trivedi |first3=Siddharth G. |last3=Adhvatyu |year=1992 |title=Role of areca nut consumption in the cause of oral cancers. A cytogenetic assessment |journal=Cancer |volume=70 |issue=5 |pages=1017–23 |pmid=1515978 |doi=10.1002/1097-0142(19920901)70:5<1017::AID-CNCR2820700502>3.0.CO;2-#|s2cid=196365532 }}</ref> As with [[chewing tobacco]], chewing betel quid with tobacco and areca nut is discouraged by [[preventive healthcare]] efforts.<ref name="StatPearls 2020"/>

Chemistry of betel leaf varies geographically and is mostly [[chavibetol]] dominant.<ref name="RimandoHan1986">{{cite journal|last1=Rimando|first1=Agnes M.|last2=Han|first2=Byung Hoon|last3=Park|first3=Jeong Hill|last4=Cantoria|first4=Magdalena C.|title=Studies on the constituents of Philippine ''Piper betle'' leaves|journal=Archives of Pharmacal Research|volume=9|issue=2|year=1986|pages=93–97|issn=0253-6269|doi=10.1007/BF02857217|s2cid=98263258}}</ref><ref name="NepaliBetelConstituent">{{citeCite journal|url=https://aromaticplant.org/pdfs/piper-betle.pdf|title= Chemical Composition and Biological Activities of Nepalese Piper betle L.|urlaccessdate=https://aromaticplant.org/pdfs/piper-betle.pdf11 March 2023}}</ref> [[Safrole]] is a major component of Sri Lankan piper''Piper betle''.<ref name="pmid22279373">{{cite journal |vauthors=Arambewela LS, Arawwawala LD, Kumaratunga KG, Dissanayake DS, Ratnasooriya WD, Kumarasingha SP |title=Investigations on ''Piper betle'' grown in Sri Lanka |journal=[[Pharmacognosy Reviews]] |volume=5 |issue=10 |pages=159–63 |date=July 2011 |pmid=22279373 |pmc=3263050 |doi=10.4103/0973-7847.91111 |issn= |doi-access=free }}</ref> [[Eugenol]], Isoeugenol[[isoeugenol]], and Germacene[[germacrene D]] are other dominant compounds in other chemotypes.<ref>{{cite journal |last1=Dwivedi |first1=Vandana |last2=Tripathi |first2=Shalini |title=Review study on potential activity of Piper betle |journal=Journal of Pharmacognosy and Phytochemistry |date=2014 |volume=3 |pages=93–98 |url=https://www.phytojournal.com/archives/2014/vol3issue4/PartB/17.1.pdf |access-date=27 September 2021}}</ref>

Leaves also contain [[eugenol]], [[chavicol]], [[hydroxychavicol]],<ref name="pmid19387769">{{cite journal |vauthors=Murata K, Nakao K, Hirata N, Namba K, Nomi T, Kitamura Y, Moriyama K, Shintani T, Iinuma M, Matsuda H |title=Hydroxychavicol: a potent xanthine oxidase inhibitor obtained from the leaves of betel, Piper betle |journal=[[Journal of Natural Medicines]] |volume=63 |issue=3 |pages=355–9 |date=July 2009 |pmid=19387769 |doi=10.1007/s11418-009-0331-y |s2cid=19647900 |issn=}}</ref><ref name="pmid30169967">{{cite journal |vauthors=Atiya A, Sinha BN, Lal UR |title=The new ether derivative of phenylpropanoid and bioactivity was investigated from the leaves of Piper betle L |journal=[[Natural Product Research]] |volume=34 |issue=5 |pages=638–645 |date=March 2020 |pmid=30169967 |doi=10.1080/14786419.2018.1495634 |s2cid=52139286 |issn=|url=https://figshare.com/articles/journal_contribution/The_new_ether_derivative_of_phenylpropanoid_and_bioactivity_was_investigated_from_the_leaves_of_i_Piper_betle_i_L_/7037525 }}</ref> and [[caryophyllene]].<ref name="NepaliBetelConstituent" />

Stems contain [[phytosterols]] ([[betaβ-sitosterol]], [[betadaucosterol|β-daucosterol]], [[stigmasterol]] etc.), [[alkaloids]] ([[piperine]], [[pellitorine]], [[piperdardine]], [[guineensine]] etc.), [[lignan]] ([[pinoresinol]]) and other bioactive components. Some of them are [[oleanolic acid]], dehydropipernonaline, piperolein-B, Bornylbornyl ''cis''-4-Hydroxycinnamatehydroxycinnamate and Bornylbornyl ''p''-Coumaratecoumarate.<ref name="pmid19764326">{{cite journal |vauthors=Yin Y, Huang XZ, Wang J, Dai JH, Liang H, Dai Y |title=[Studies on the chemical constituents of the stems of Piper betle] |language=Chinese |journal=[[ Zhong Yao Cai = Zhongyaocai = Journal of Chinese Medicinal Materials]] |volume=32 |issue=6 |pages=887–90 |date=June 2009 |pmid=19764326 |issn=}}</ref><ref name="pmid21137339">{{cite journal |vauthors=Huang X, Yin Y, Huang W, Sun K, Cheng C, Bai L, Dai Y |title=[Alkaloids and lignans from stems of Piper betle] |language=Chinese |journal=[[ Zhongguo Zhong Yao Za Zhi = Zhongguo Zhongyao Zazhi = China Journal of Chinese Materia Medica]] |volume=35 |issue=17 |pages=2285–8 |date=September 2010 |pmid=21137339 |issn=}}</ref><ref name="pmid32466337">{{cite journal |vauthors=Wu YJ, Su TR, Chang CI, Chen CR, Hung KF, Liu C |title=(+)-Bornyl p-Coumarate Extracted from Stem of Piper betle Induced Apoptosis and Autophagy in Melanoma Cells |journal=[[International Journal of Molecular Sciences]] |volume=21 |issue=10 |date=May 2020 |page=3737 |pmid=32466337 |pmc=7279146 |doi=10.3390/ijms21103737 |issn=|doi-access=free }}</ref><ref name="pmid29734677">{{cite journal |vauthors=Yang TY, Wu YJ, Chang CI, Chiu CC, Wu ML |title=The Effect of Bornyl cis-4-Hydroxycinnamate on Melanoma Cell Apoptosis Is Associated with Mitochondrial Dysfunction and Endoplasmic Reticulum Stress |journal=[[International Journal of Molecular Sciences]] |volume=19 |issue=5 |date=May 2018 |page=1370 |pmid=29734677 |pmc=5983650 |doi=10.3390/ijms19051370 |issn=|doi-access=free }}</ref>

Roots contain aristololactam A-II, a new [[phenylpropene]], 4-allyl resorcinol and a diketosteroid stigmast-4-en-3,6-dione.<ref name="pmid18007349">{{cite journal |vauthors=Ghosh K, Bhattacharya TK |title=Chemical constituents of ''Piper betle'' Linn. (Piperaceae) roots |journal=[[Molecules (Basel, Switzerland)]] |volume=10 |issue=7 |pages=798–802 |date=August 2005 |pmid=18007349 |pmc=6147577 |doi=10.3390/10070798 |url= |issn= |doi-access=free }}</ref>

EssentialIts [[essential oil]] consistedconsists of 50 different compounds, of which major components are eugenol, caryophyllene, [[terpinolene]], [[terpinene]], [[cadinene]], and [[3-carene]].<ref name="DasParida2016">{{cite journal|last1=Das|first1=Suryasnata|last2=Parida|first2=Reena|last3=Sandeep|first3=I. Sriram|last4=Kar|first4=Basudev|last5=Nayak|first5=Sanghamitra|last6=Mohanty|first6=Sujata|title=Chemical composition and antioxidant activity of some important betel vine landraces|journal=Biologia|volume=71|issue=2|year=2016|pages=128–132|issn=1336-9563|doi=10.1515/biolog-2016-0030|s2cid=88132584}}</ref>

Betel vines are cultivated throughout southeast Asia, in plots whose area is typically 20 to 20002,000 square metres (0.005 to 0.5 acre) in size.

Malaysian farmers cultivate four types of betel plants: sirih India, sirih Melayu, sirih Cina and sirih Udang. The harvest is then sold in bundles of leaves, each bundle costing in 2011 between MYR 0.30 toand 0.50 ($0.07 toand $0.12).

In Sri Lanka, betel is grown all over the country, but the. commercialCommercial production of betel, with bigger leaves with dark green colour combined with thickness, known as “kalu bulath”, is confined to a few districts, such as [[Kurunegala District|Kurunagala]], [[Gampaha District|Gampaha]], [[Kegalle District|Kegalle]], [[Kalutara District|Kalutara]] and [[Colombo District|Colombo]].<ref name=LK>{{cite web |title= Betel – Piper Betle L |author= Government of Sri Lanka |url= http://www.exportagridept.gov.lk/web/index.php?option=com_content&view=article&id=126&Itemid=159&lang=ta |access-date= 2011-07-31 |archive-url= https://web.archive.org/web/20160514054345/http://www.exportagridept.gov.lk/web/index.php?option=com_content&view=article&id=126&Itemid=159&lang=ta |archive-date= 2016-05-14 |url-status= dead }}</ref> These are sold at a wholesaler in lots of 10001,000 leaves. According to a report published by the [[United Nations]] [[Food and Agriculture Organization]] (FAO),<ref>{{cite web|title = Success Case Replication – A Manual for Increasing Farmer Household Income, see case study 12 in the report|author=Jan B. Orsini|url=http://www.fao.org/docrep/004/AC159E/ac159e00.HTM}}</ref> a successful betel farm in Sri Lanka can provide a supplemental income to a farmer by providing six days of work every six months and net income when the leaf prices are attractive. The FAO study found the successful farm's yield to be 18,000 leaves per {{convert|150|sqft|m2}}. The additional salary and income to the Sri Lankan betel grower, assuming he or she provides all needed labor and keeps all net profit, is SL Rs. 1635 per {{convert|150|sqft|m2}} of betel farm every 6 months ($90 per "[[decimal]]" per year, or $9000 per acre per year). If the farmer hires outside labor to tend the betel vines and harvest the crop, the FAO found the net income to the betel farm owner to be SL Rs. 735 per {{convert|150|sqft|m2}} of betel farm every six months ($40 per decimal per year, or $4000 per acre per year). According to FAO, the market prices for betel leaves vary with wet and dry season in Sri Lanka, and in 2010 averaged SL Rs. 200–400 per 1000 leaves ($1.82 to $3.64 per 1000 leaves).<ref>{{cite web|title=Life in the hill country of Sri Lanka|publisher=The Food and Agriculture Organization of United Nations|url=http://www.fao.org/getinvolved/telefood/telefood-projects/slideshows/life-in-the-hill-country-of-sri-lanka/en/ }}</ref> The FAO study assumes no losses from erratic weather and no losses during storage and transportation of perishable betel leaves. These losses are usually between 35% to 70%.<ref name=GUHA/>

*The Merck Manual. Tumours of The head and neck. [http://www.merck.com/mmpe/sec08/ch093/ch093a.html Introduction to Inner Ear Disorders - Ear, Nose, and Throat Disorders]

* {{Commons-inline|Piper betle}}