Flatulence and Wind

oPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.

Flatulence and wind are symptoms related to gas in the gastrointestinal (GI) system. 'Flatulence' usually refers to gas passed per rectum. 'Wind' as a symptom may mean either belching (gas passed from the stomach outwards via the mouth), or gas passed per rectum (or even just feeling bloated). 'Eructation' is another term for belching.

Flatulence and belching are common symptoms in the general population.[1]

Belching:

  • This is the release of gas from the stomach, either voluntary or involuntary. It is a normal reflex which occurs most commonly after meals, releasing swallowed air.
  • There may be 2 types of excessive belching:[2]
    • Supragastric belching, where air is sucked into and expelled from the pharynx only.
    • Aerophagia, where there is excess swallowing of air into the stomach.

Flatulence:

  • Intestinal bacterial colonies produce gases. Carbon dioxide, hydrogen and methane are responsible for the main volume of intestinal gas, and sulphur-containing gases for malodour.[3]
  • The volume and composition of gas depends both on diet and on colonic flora.[4][5]
  • A large volume of gas probably does not cause symptoms in healthy people, because it is easily expelled.[6]

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Belching

  • Diet/lifestyle factors, eg eating too quickly, fizzy drinks, chewing gum, smoking.
  • Antacids - produce carbon dioxide gas which may contribute.
  • Dyspepsia or reflux - patients may swallow air and may belch in an attempt to relieve upper GI symptoms.[7]
  • Giardiasis - can cause malodorous belching.[8]

Flatulence

Symptoms may be due to excessive volume of gas or to malodour. Possible causes or contributing factors are:

  • Clarify what most bothers the patient about their symptoms.
  • 'Red flags', eg dysphagia, weight loss, rectal bleeding, change in bowel habit with looser stools in patients aged >60, family history of bowel cancer.[12]
  • Clinical examination (if relevant) to look for any serious signs, eg anaemia, nodes, and abdominal, pelvic or rectal masses.

These depend on the clinical picture. Basic tests may be relevant to help rule out other problems (eg as recommended in the diagnosis of irritable bowel syndrome[12]):

  • Full blood count (FBC).
  • Erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP).
  • Antibody testing for coeliac disease.

Breath tests may be used to assess intestinal flora and small intestinal bacterial overgrowth, usually in the context of research studies.[10]

Belching

  • Explanation of normal physiology and reassurance may be sufficient.
  • Investigate/treat dyspepsia and reflux symptoms if relevant.[13]
  • Speech therapy or behavioural therapy may be used.[2][13]

Flatulence

Note that most of the research and literature on this topic relates to patients diagnosed with irritable bowel syndrome. Possible treatments are:

  • Mild physical activity - has been shown to enhance gas clearance in a study of patients with bloating.[14]
  • Treating exacerbating factors such as constipation.
  • Diet:
    • Soluble fibre such as linseed (up to 1 tablespoon daily) and oats.[12]
    • Diets low in fermentable carbohydrate can reduce flatulence in irritable bowel syndrome.[15][16]
  • Probiotics:[4][9][12]
    • These are 'gut-friendly' bacteria such as lactobacilli and bifidobacteria. They can alter colonic fermentation and inhibit gas-producing bacteria such as Clostridium spp.
    • They have been shown to reduce flatulence in patients with irritable bowel syndrome.
    • The specific strain of bacteria may be important but, on current evidence, it is difficult to advise which strain(s) to use.
  • Drugs:
    • Antibiotics, eg metronidazole[10] or rifaximin.[17], can be used to treat small intestinal bacterial overgrowth.
    • Simeticone combined with loperamide may improve gas symptoms in acute diarrhoea.[3]
    • Oral bismuth subsalicylate binds sulphide gases in the gut, but is not safe for regular use due to the salicylate content.[3]
  • Supplements:
    • Alpha-galactosidase, an enzyme supplement, has been shown to reduce flatus after eating beans.[18]
  • Odour reduction devices:
    • Garment devices containing activated charcoal have been tested in one trial. This found that briefs containing charcoal were effective, but pads and cushions of the same material were less helpful.[19]

Further reading & references

  1. van Kerkhoven LA, Eikendal T, Laheij RJ, et al; Gastrointestinal symptoms are still common in a general Western population. Neth J Med. 2008 Jan;66(1):18-22.
  2. Bredenoord AJ; Excessive belching and aerophagia: two different disorders. Dis Esophagus. 2010 May;23(4):347-52. Epub 2010 Jan 20.
  3. Bailey J, Carter NJ, Neher JO; FPIN's Clinical Inquiries: Effective management of flatulence. Am Fam Physician. 2009 Jun 15;79(12):1098-100.
  4. Spiller R; Review article: probiotics and prebiotics in irritable bowel syndrome. Aliment Pharmacol Ther. 2008 Aug 15;28(4):385-96. Epub 2008 Jun 4.
  5. Bixquert Jimenez M; Treatment of irritable bowel syndrome with probiotics. An etiopathogenic approach Rev Esp Enferm Dig. 2009 Aug;101(8):553-64.
  6. Azpiroz F; Intestinal gas dynamics: mechanisms and clinical relevance. Gut. 2005 Jul;54(7):893-5.
  7. Hemmink GJ, Bredenoord AJ, Weusten BL, et al; Supragastric belching in patients with reflux symptoms. Am J Gastroenterol. 2009 Aug;104(8):1992-7. Epub 2009 May 19.
  8. Pennardt M; Giardiasis, eMedicine, Apr 2009
  9. Moayyedi P, Ford AC, Talley NJ, et al; The efficacy of probiotics in the treatment of irritable bowel syndrome: a Gut. 2010 Mar;59(3):325-32. Epub 2008 Dec 17.
  10. Gasbarrini A, Lauritano EC, Gabrielli M, et al; Small intestinal bacterial overgrowth: diagnosis and treatment. Dig Dis. 2007;25(3):237-40.
  11. Lomer MC, Parkes GC, Sanderson JD; Review article: lactose intolerance in clinical practice--myths and realities. Aliment Pharmacol Ther. 2008 Jan 15;27(2):93-103. Epub 2007 Oct 23.
  12. Irritable bowel syndrome; NICE Clinical Guideline (February 2008)
  13. Bredenoord AJ, Smout AJ; Physiologic and pathologic belching. Clin Gastroenterol Hepatol. 2007 Jul;5(7):772-5. Epub 2007 May 4.
  14. Villoria A, Serra J, Azpiroz F, et al; Physical activity and intestinal gas clearance in patients with bloating. Am J Gastroenterol. 2006 Nov;101(11):2552-7. Epub 2006 Oct 4.
  15. Staudacher HM et al; Implementation of the low-fermentable oligo-, di-, mono-saccharides and polyols diet in the UK: how easy is it and does it work? Gut March 2010 Vol 59 No 4 (doi:10.1136/gut.2009.209049y)
  16. Barrett JS, Gibson PR; Clinical Ramifications of Malabsorption of Fructose andOther Short-chain Carbohydrates. Practical Gastroenterology, August 2007
  17. Di Stefano M, Strocchi A, Malservisi S, et al; Non-absorbable antibiotics for managing intestinal gas production and gas-related Aliment Pharmacol Ther. 2000 Aug;14(8):1001-8.
  18. Di Stefano M, Miceli E, Gotti S, et al; The effect of oral alpha-galactosidase on intestinal gas production and gas-related symptoms. Dig Dis Sci. 2007 Jan;52(1):78-83. Epub 2006 Dec 7.
  19. Ohge H, Furne JK, Springfield J, et al; Effectiveness of devices purported to reduce flatus odor. Am J Gastroenterol. 2005 Feb;100(2):397-400.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Naomi Hartree
Current Version:
Last Checked:
26/10/2010
Document ID:
1570 (v22)
© EMIS