Abdominal Distension and Bloating

Last updated by Peer reviewed by Dr Surangi Mendis
Last updated Meets Patient’s editorial guidelines

Added to Saved items
This article is for Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the Trapped Wind, Gas and Bloating article more useful, or one of our other health articles.

Read COVID-19 guidance from NICE

Treatment of almost all medical conditions has been affected by the COVID-19 pandemic. NICE has issued rapid update guidelines in relation to many of these. This guidance is changing frequently. Please visit https://www.nice.org.uk/covid-19 to see if there is temporary guidance issued by NICE in relation to the management of this condition, which may vary from the information given below.

Abdominal distension may be generalised, or may be localised to a discrete mass or enlargement of an organ. The main causes of generalised abdominal distension are easily remembered by the five Fs:

  • Fat (obesity).
  • Faeces (constipation).
  • Fetus (pregnancy).
  • Flatus (gastrointestinal).
  • Fluid (ascites).

The most common causes are:

Non-obstructive causes

Mechanical bowel obstruction

Non-mechanical bowel obstruction

  • Vascular insufficiency: thrombosis, embolism.
  • Retroperitoneal irritation: renal colic, neoplasm, infection.
  • Extra-abdominal infection: sepsis, pneumonia, empyema, spinal osteomyelitis.
  • Metabolic/toxic: hypokalaemia, uraemia, lead poisoning.
  • Chemical irritation: perforated peptic ulcer, pancreatitis, biliary peritonitis.
  • Miscellaneous: excessive intraluminal gas, intra-abdominal infection, trauma, mechanical ventilation, other causes of peritoneal inflammation, severe pain and non-steroidal anti-inflammatory drugs (NSAIDs).

Right upper quadrant

Left upper quadrant

See the separate Left Upper Quadrant Pain article for further detail.


  • Abdominal wall - eg, lipoma, hernia.
  • Stomach - eg, carcinoma, distension due to pyloric stenosis.
  • Pancreas - eg, pseudocyst, carcinoma.
  • Transverse colon - eg, carcinoma, faeces, diverticular mass.
  • Hepatomegaly.
  • Retroperitoneum - eg, aortic aneurysm, lymphadenopathy.
  • Omentum - eg, secondaries from stomach or ovary.


  • Hernia, paraumbilical or umbilical.
  • Stomach - eg, carcinoma.
  • Transverse colon - eg, carcinoma, faeces, diverticular mass.
  • Small bowel - eg, Crohn's disease.
  • Omentum - eg, secondaries from stomach or ovary.
  • Retroperitoneum - eg, aortic aneurysm, lymphadenopathy.

Right and left lower quadrants


  • Careful history taking and abdominal examination are essential. Clinical assessment will usually indicate the nature of abdominal distension (ie whether ascites, gastrointestinal gas, pregnancy, etc) but further investigations are often required to determine the precise aetiology.
  • Resonance on percussion may be misleading because there may be bowel overlying a solid tumour or enlarged organ.
  • Weight loss associated with abdominal distension suggests malignancy.
  • Constipation needs to be fully evaluated to establish any underlying cause.
  • Obesity may make examination very difficult to provide a clear assessment and an ultrasound scan or cross-sectional imaging may then be required, irrespective of the likely cause of distension.

These should be directed by history and examination and tailored to each patient. Possible investigations include:

  • FBC: raised white cell count in infection or malignancy, anaemia with abnormal vaginal bleeding associated with fibroids, or as a consequence of malignancy.
  • U&Es: renal dysfunction; hypokalaemia or uraemia may cause non-mechanical bowel obstruction.
  • LFTs: liver failure, cholestatic hyperbilirubinaemia with carcinoma of pancreas, hypoalbuminaemia associated with ascites.
  • Coeliac serology.
  • CA 125: in women, particularly postmenopausal women, to look for evidence of ovarian cancer. (Note though that CA 125 is nonspecific - it is physiologically elevated during menstruation, the first trimester of pregnancy, and postpartum, and can also increase due to endometriosis, uterine fibroids, and non-malignant ascites, amongst other things.)
  • C-reactive protein, if inflammation/infection is suspected.
  • Faecal calprotectin.
  • Urinalysis: may show haematuria in patients with tumours of kidney or bladder.
  • Pregnancy test.
  • Quantitative faecal immunochemical (qFIT) testing: colorectal cancer.
  • Abdominal X-ray, barium enema: constipation, large bowel pathology, bowel obstruction.
  • Abdominal ultrasound.
  • Transvaginal ultrasound.
  • Oesophagogastroduodenoscopy (OGD).
  • Sigmoidoscopy, colonoscopy.
  • Further investigations might include CT scans and paracentesis.
  • Referral decisions depend upon the underlying cause; many causes can be managed, at least initially, in primary care (such as IBS).
  • In general, referral is recommended if there is abdominal distension without any clear diagnosis.

Bloating is a very common and subjective ailment which can affect patients of all ages. It can be associated with any of the causes of abdominal distension but it is most commonly associated with irritable bowel syndrome. Bloating can have a major impact both socially and psychologically. It is incompletely understood and often inadequately treated.

Interventions include:[1]

  • Keeping a food and symptom diary to identify and avoid triggers.
  • Avoiding artificial sweeteners containing poorly-absorbed sugar alcohols (eg, sorbitol, mannitol and xylitol).
  • Following a low FODMAP diet.
  • Probiotics (although evidence is limited).
  • Antispasmodics, such as mebeverine, peppermint oil, and hyoscine butylbromide.
  • Secretagogues, such as linaclotide.
  • Neuromodulatory drugs, such as amitriptyline and some SSRIs.
  • Biofeedback therapy.
  • Gut-directed hypnotherapy.

For further information see the related separate Irritable Bowel Syndrome article.

  • Sigmoidoscopy, colonoscopy.

Are you protected against flu?

See if you are eligible for a free NHS flu jab today.

Check now

Further reading and references

  • Iovino P, Bucci C, Tremolaterra F, et al; Bloating and functional gastro-intestinal disorders: where are we and where are we going? World J Gastroenterol. 2014 Oct 2120(39):14407-19. doi: 10.3748/wjg.v20.i39.14407.

  • Bendezu RA, Mego M, Monclus E, et al; Colonic content: effect of diet, meals, and defecation. Neurogastroenterol Motil. 2017 Feb29(2). doi: 10.1111/nmo.12930. Epub 2016 Aug 21.

  • Talley NJ, Goodsall T, Potter M; Functional dyspepsia. Aust Prescr. 2017 Dec40(6):209-213. doi: 10.18773/austprescr.2017.066. Epub 2017 Dec 4.

  • Mari A, Abu Backer F, Mahamid M, et al; Bloating and Abdominal Distension: Clinical Approach and Management. Adv Ther. 2019 May36(5):1075-1084. doi: 10.1007/s12325-019-00924-7. Epub 2019 Mar 16.

  • Moshiree B, Drossman D, Shaukat A; AGA Clinical Practice Update on Evaluation and Management of Belching, Abdominal Bloating, and Distention: Expert Review. Gastroenterology. 2023 Sep165(3):791-800.e3. doi: 10.1053/j.gastro.2023.04.039. Epub 2023 Jul 13.

  1. Lacy BE, Cangemi D, Vazquez-Roque M; Management of Chronic Abdominal Distension and Bloating. Clin Gastroenterol Hepatol. 2021 Feb19(2):219-231.e1. doi: 10.1016/j.cgh.2020.03.056. Epub 2020 Apr 1.