View source for Belching

{{BioPsy}}

{{SignSymptom infobox |

  Name        = Eructation |
  ICD10       = {{ICD10|R|14||r|10}} |
  ICD9        = {{ICD9|787.3}} |
}}
''' Belching''', also known as '''burping''', '''ructus''', or '''eructation''', involves the release of [[gas]] from the digestive tract (mainly [[esophagus]] and [[stomach]]) through the [[mouth]]. It is usually accompanied with a typical sound and, at times, an [[halitosis|odor]].

==Physiology==
Belching is typically caused by swallowing air ([[aerophagia]]) when eating or drinking and subsequently expelling it, so in this case the expelled gas is mainly a mixture of [[nitrogen]] and [[oxygen]]. Burps can also be caused by drinking [[carbonation|carbonated]] drinks such as [[beer]], [[soft drink]]s, or [[Champagne (wine)|champagne]], in which case the expelled  gas is [[carbon dioxide]] from the drink itself. Common diabetes drugs metformin <ref>[http://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?id=3653 DailyMed: About DailyMed]</ref> and Byetta <ref>[http://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?id=5430 DailyMed: About DailyMed]</ref> can cause belching, especially at higher doses. This often resolves in a few weeks. Belching combined with other symptoms such as [[dyspepsia]], [[nausea]] and [[heartburn]] may be a sign of an [[Peptic ulcer|ulcer]] or [[hiatal hernia]], and should be reviewed by a physician. <ref>[http://wrongdiagnosis.com/symptoms/belching/book-causes-8c.htm Eructation (Professional Guide to Signs & Symptoms (Fifth Edition)) - WrongDiagnosis.com]</ref>

The sound of burping is caused by the [[oscillation|vibration]] of the [[upper esophageal sphincter]]<ref>[http://www.nature.com/gimo/contents/pt1/full/gimo12.html GI Motility online: Upper esophageal sphincter - Ivan M. Lang, D.V.M., Ph.D.]</ref> as the gas passes through it. The current [[Guinness world record]] for the loudest burp is 107.1 [[Decibel|dB]], set by Paul Hunn in 2008.<ref>http://www.guinnessworldrecords.com/records/human_body/extreme_bodies/loudest_burp.aspx</ref> (This would be noticeably louder than a chainsaw at a distance of 1 metre.) 

==Terminology==

In the [[United States]], "burping" is significantly quieter and subtler than "belching".

==Social context and etiquette==
In many parts of the world, especially in formal situations, audible burping is considered impolite. Public belching tends to be received in a manner similar to [[flatulence]].

==Infant burping==
[[Infant|Babies]] are particularly subject to accumulation of gas in the stomach while feeding, and this can cause considerable agitation and/or discomfort to the child unless it is ''burped''. The act of burping an infant involves placing the child in a position conducive to gas expulsion (for example holding the infant up to the adult's shoulder, with the infant's stomach resting on the adult's chest) and then lightly patting it on the lower back so that he or she burps. This practice is not universal, for instance in the [[Czech Republic]], there is no tradition of burping babies.<ref>Common Sense about Babies and Children, H Jolly - 1983 - Unwin Paperbacks</ref>

Because burping can cause [[vomiting]] in infants, the ''burp cloth'' or ''burp pad'' is sometimes employed on the shoulder to protect the adult's clothing.

== In animals ==
Many other [[mammal]]s, such as [[cattle]], [[dog]]s, and [[sheep]] also burp. In the case of [[ruminant]]s, the gas expelled is actually methane produced as a byproduct of the animal's [[digestion|digestive process]]. [[Anaerobic organism]]s such as ''Escherichia coli'' (''E. coli'') and methanogenic archaea produce this effect. An average cow is thought to emit between 542 [[litre]]s (if located in a barn) and 600 litres (if in a field) of methane per day through burping and exhalation, making commercially farmed cattle a major contributor to the greenhouse effect.  95% of this gas is emitted through belching.<ref>[http://www.mycattle.com/health/dsp_health_article.cfm?storyid=10045 MyCattle Health News]</ref> This has led scientists at the Commonwealth Scientific and Industrial Research Organisation of Perth, Western Australia,to develop an anti-methanogen vaccine to minimize methane in cattle burps.<ref>[http://www.newscientist.com/article.ns?id=dn6431 Burp vaccine cuts greenhouse gas emissions] - New Scientist</ref>

One reason that domesticated cows burp so much is because they are often fed foods that their digestive systems did not evolve to process, such as corn and soy. Some farmers have reduced burping in their cows by feeding them alfalfa and flaxseed, which are closer to the grasses that they had eaten in the wild, before they were domesticated.<ref>[http://www.nytimes.com/2009/06/05/us/05cows.html Greening the Herds: A New Diet to Cap Gas], New York Times, June 4, 2009</ref>

In some animals, a failure to burp successfully can be fatal.  This is particularly common among domesticated ruminants that are allowed to gorge themselves on very rich spring clover or alfalfa.  The condition, known as [[bloat]] is basically a high pressure build up of gastric gasses and requires immediate veterinary treatment, usually the insertion of a flexible rubber hose down the esophagus or in extreme cases the lancing of the animal's side with a scalpel to expel the build up of gas.

Some [[fish]] are also known to expel air from their gills; here the burp is produced by gas being expelled from the [[gas bladder]].

==see also==
* [[Aerophagia]] - swallowing of air

==References==
{{Refimprove|date=January 2008}}
{{reflist}}

==External links==
*[http://rucus.ru.ac.za/~wolfman/Essays/Cow.html Cow methane production]
*[http://www.webmd.com/hw/heartburn/aa113156.asp from Webmd.com]

{{Digestive system and abdomen symptoms and signs}}

[[Category:Behavior]]
[[Category:Digestive system]]
[[Category:Excretion]]
[[Category:Symptoms]]

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