Irritable Bowel Syndrome


  • Recurrent abdominal pain or discomfort that is associated with a change in stool frequency or form
  • Pain or discomfort often relieved by defecation
  • Bloating
  • Stomach cramps
  • Bouts of diarrhoea and constipation


Attempt to identify dietary associations with symptoms such as lactose-containing foods or fructose-containing foods

Ask the patient has worrying symptoms or findings suggesting including:

  • Anaemia
  • Weight loss
  • Fever


Examination of the abdomen is usually unremarkable. There may be mild and poorly localised tenderness in the RLQ and/or LLQ.


  • Inflammatory bowel disease
  • Coeliac disease
  • Colon cancer

Laboratory investigations

To exclude other diagnoses:

  • FBC
    • Normal - anaemia would suggest a non-IBS condition
  • ESR or plasma viscosity
  • CRP
  • Anti-endomysial antibodies and anti-tTG antibodies
    • Serological testing for coeliac disease

Faecal calprotectin testing

  • Helps doctors distinguish between inflammatory bowel diseases e.g Crohn’s disease and ulcerative colitis, and non-inflammatory bowel diseases e.g irritable bowel syndrome


  • A radioactive drug used to diagnose bile acid malabsorption, which can cause long-lasting debilitating diarrhoea


Consider diagnosing IBS only if the person has abdominal pain or discomfort that is:

  • relieved by defaecation OR associated with altered bowel frequency or stool form

AND at least 2 of the following:

  • Altered stool passage (straining, urgency, incomplete evacuation)
  • Abdominal bloating (more common in women than men), distension, tension or hardness
  • Symptoms made worse by eating
  • Passage of mucus.
  • Lethargy, nausea, backache and bladder symptoms may be used to support diagnosis

The following tests are NOT required to confirm IBS in those who meet the diagnostic criteria:

  • Ultrasound
  • Rigid/flexible sigmoidoscopy
  • Colonoscopy; barium enema
  • Thyroid function test
  • Faecal ova and parasite test
  • Faecal occult blood
  • Hydrogen breath test (for lactose intolerance and bacterial overgrowth)



  • Have regular meals and take time to eat.
  • Avoid missing meals or leaving long gaps between eating.
  • Drink at least 8 cups of fluid per day, especially water or other non-caffeinated drinks such as herbal teas.
  • Restrict tea and coffee to 3 cups per day and reduce intake of alcohol and fizzy drinks.
  • Consider limiting intake of high-fibre food (for example, wholemeal or high-fibre flour and breads, cereals high in bran, and whole grains such as brown rice).
  • Reduce intake of starch that resists digestion in the small intestine and reaches the colon intact - this is often found in processed or re-cooked foods.
  • Limit fresh fruit to 3 portions (of 80 g each) per day.
  • For wind and bloating consider increasing intake of oats (e.goat-based breakfast cereal or porridge)
  • Review the person's fibre intake and adjust according to symptoms
  • Discourage intake of insoluble fibre (for example, bran).
  • If more fibre is needed, recommend soluble fibre such as ispaghula powder, or foods high in soluble fibre (for example, oats)

Encourage physical activity

First-Line Pharmacological treatment

  • Antispasmodic agents
  • Laxatives for constipation
    • Discourage use of lactulose
    • Consider linaclotide if previous laxatives have failed AND the patient has had constipation for at least 12 months
  • Antimotility agents for diarrhoea
    • Loperamide

Psychological Intervention

  • For patients not responding to pharmacological treatment
  • Interventions include:
    • CBT
    • Hypnotherapy
    • Psychological therapy

Complementary medicine

Do not encourage use of acupuncture or reflexology for the treatment of irritable bowel syndrome


  • IBS has few complications - It does not lead to rectal bleeding, colon cancer, or inflammatory bowel diseases
  • Diarrhea and constipation may aggravate hemorrhoids in people who already have them


  • Symptoms fluctuate over many years
  • People with a long history of IBS are unlikely to improve
Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License