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 two 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 sulfur-containing gases for malodour.[3]
  • The volume and composition of gas depends both on diet and on colonic flora.[4][5]
  • Peope with irritable bowel syndrome (IBS) are likely to produce a greater volume of gas than people who do not have IBS. IBS is also associated with a positive lactulose breath test (a test that assesses the amount of fermented gas generated by bacteria in the bowel) and an increase in gas-related symptoms. This would seem to counteract previous theories that there is no difference in the amount of gas produced by IBS and non-IBS individuals but that non-IBS people are simply more tolerant of large gas volumes.[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:

  • Diets high in fermentable carbohydrate (eg, pulses, bran and fruit).[3]
  • Variations in bowel flora composition.[4][5]
  • Constipation.[9]
  • IBS.[10]
  • Acute gastroenteritis.[3]
  • Giardiasis.[8] 
  • Small intestinal bacterial overgrowth.[11]
  • Lactose intolerance.[12]
  • Malabsorption.
  • Flatulence (and belching) are common in female runners. The cause for this has yet to be elucidated.[13] 
  • 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.[14]
  • 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):[14]

  • FBC.
  • ESR or 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.[11]

Belching

  • Explanation of normal physiology and reassurance may be sufficient.
  • Investigate/treat dyspepsia and reflux symptoms if relevant.[2] 
  • Speech therapy or behavioural therapy may be used.[2][15]

Flatulence

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

  • Mild physical activity - has been shown to enhance gas clearance in a study of patients with bloating.[16] 
  • Treating exacerbating factors such as constipation.
  • Diet:
    • Soluble fibre such as linseed (up to one tablespoon daily) and oats.[14]
    • Diets low in fermentable carbohydrate can reduce flatulence in IBS.[17] 
  • Probiotics:[18] 
    • These are 'gut-friendly' bacteria such as lactobacilli and bifidobacteria.
    • Their mechanism of action is unclear but they can alter colonic fermentation and inhibit gas-producing bacteria such as Clostridium spp. They have an effect on intestinal motility and may also have an anti-inflammatory effect on mucosal cells.
    • They have been shown to reduce flatulence in patients with IBS.
    • 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 or rifaximin) can be used to treat small intestinal bacterial overgrowth.[11][19] One study reported that rifaximin was more effective and better tolerated than metronidazole.[20] 
    • Simeticone combined with loperamide may improve gas symptoms in acute diarrhoea.[3] Neither simeticone nor activated charcoal has a beneficial effect in IBS-related gas symptoms.[21] 
    • Oral bismuth subsalicylate binds sulfide 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.[22]One study reported that it is particularly effective in children.[23] 
  • 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.[24]

Further reading & references

  • Morabito G, Romeo C, Romano C; Functional aerophagia in children: a frequent, atypical disorder. Case Rep Gastroenterol. 2014 Apr 5;8(1):123-8. doi: 10.1159/000362441. eCollection 2014 Jan.
  • Manichanh C, Eck A, Varela E, et al; Anal gas evacuation and colonic microbiota in patients with flatulence: effect of diet. Gut. 2014 Mar;63(3):401-8. doi: 10.1136/gutjnl-2012-303013. Epub 2013 Jun 13.
  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. Youn YH, Park JS, Jahng JH, et al; Relationships among the lactulose breath test, intestinal gas volume, and gastrointestinal symptoms in patients with irritable bowel syndrome. Dig Dis Sci. 2011 Jul;56(7):2059-66. doi: 10.1007/s10620-011-1569-2. Epub 2011 Jan 15.
  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. Santacroce L, Bottalico L, Mangini F; Dental hygiene procedure in a patient with Giardia lamblia infection. Int J Dent Hyg. 2007 Aug;5(3):187-9.
  9. Azpiroz F; Intestinal gas dynamics: mechanisms and clinical relevance. Gut. 2005 Jul;54(7):893-5.
  10. 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.
  11. Gasbarrini A, Lauritano EC, Gabrielli M, et al; Small intestinal bacterial overgrowth: diagnosis and treatment. Dig Dis. 2007;25(3):237-40.
  12. 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.
  13. Ten Haaf DS, van der Worp MP, Groenewoud HM, et al; Nutritional indicators for gastrointestinal symptoms in female runners: the 'Marikenloop study'. BMJ Open. 2014 Aug 4;4(8):e005780. doi: 10.1136/bmjopen-2014-005780.
  14. Irritable bowel syndrome in adults; NICE Clinical Guideline (February 2008)
  15. Bredenoord AJ, Smout AJ; Physiologic and pathologic belching. Clin Gastroenterol Hepatol. 2007 Jul;5(7):772-5. Epub 2007 May 4.
  16. Lacy BE, Gabbard SL, Crowell MD; Pathophysiology, evaluation, and treatment of bloating: hope, hype, or hot air? Gastroenterol Hepatol (N Y). 2011 Nov;7(11):729-39.
  17. Staudacher HM, Whelan K, Irving PM, et al; Comparison of symptom response following advice for a diet low in fermentable carbohydrates (FODMAPs) versus standard dietary advice in patients with irritable bowel syndrome. J Hum Nutr Diet. 2011 Oct;24(5):487-95. doi: 10.1111/j.1365-277X.2011.01162.x. Epub 2011 May 25.
  18. Lee KN, Lee OY; Intestinal microbiota in pathophysiology and management of irritable bowel syndrome. World J Gastroenterol. 2014 Jul 21;20(27):8886-8897.
  19. Scarpellini E, Giorgio V, Gabrielli M, et al; Rifaximin treatment for small intestinal bacterial overgrowth in children with irritable bowel syndrome. Eur Rev Med Pharmacol Sci. 2013 May;17(10):1314-20.
  20. Lauritano EC, Gabrielli M, Scarpellini E, et al; Antibiotic therapy in small intestinal bacterial overgrowth: rifaximin versus metronidazole. Eur Rev Med Pharmacol Sci. 2009 Mar-Apr;13(2):111-6.
  21. Occhipinti K, Smith JW; Irritable bowel syndrome: a review and update. Clin Colon Rectal Surg. 2012 Mar;25(1):46-52. doi: 10.1055/s-0032-1301759.
  22. 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.
  23. Di Nardo G, Oliva S, Ferrari F, et al; Efficacy and tolerability of alpha-galactosidase in treating gas-related symptoms in children: a randomized, double-blind, placebo controlled trial. BMC Gastroenterol. 2013 Sep 24;13:142. doi: 10.1186/1471-230X-13-142.
  24. 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:
Peer Reviewer:
Prof Cathy Jackson
Last Checked:
21/08/2014
Document ID:
1570 (v23)
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