Irritable Bowel Syndrome (IBS)

A common, manageable disorder of gut–brain interaction

What is IBS?

IBS is one of the most common gut conditions, affecting around 1 in 10 Australians. It causes recurrent abdominal pain linked to changes in bowel habit — constipation, diarrhoea, or both. IBS is called a disorder of gut–brain interaction: the gut is more sensitive than usual and the normal two-way communication between the gut and the brain is disturbed. Importantly, IBS does not damage the bowel and does not increase your risk of bowel cancer.

Typical symptoms

• Abdominal pain or cramping, often related to bowel movements

• Bloating and visible abdominal distension

• Diarrhoea, constipation, or alternating between the two

• A feeling of incomplete emptying after a bowel motion

• Symptoms that fluctuate — often worse with stress or after certain meals

How is IBS diagnosed?

IBS is diagnosed on the pattern of symptoms, together with simple tests to exclude other conditions — typically blood tests (including coeliac serology), and a stool test called faecal calprotectin, which helps distinguish IBS from inflammatory bowel disease. Colonoscopy is not needed for everyone, but we recommend it when there are warning signs or when symptoms begin later in life.

Treatment — a stepwise approach

• Diet: regular meal patterns, adequate fluid, and moderating caffeine, alcohol and fatty foods. A dietitian-guided low FODMAP diet helps around 3 in 4 people with IBS (see our separate handout).

• Fibre: soluble fibre such as psyllium helps many people, particularly with constipation-predominant IBS.

• Medications: antispasmodics for cramping, laxatives or anti-diarrhoeal agents depending on your pattern, and peppermint oil capsules for some.

• Gut–brain therapies: low-dose tricyclic medications (used for pain, not depression), gut-directed hypnotherapy and cognitive behavioural therapy have strong evidence in IBS.

• Exercise, sleep and stress management all measurably improve symptoms.

⚠ See a doctor promptly if you have Blood in the stool or black stoolsUnintentional weight lossSymptoms waking you from sleepNew bowel symptoms starting after age 50Fever, persistent vomiting, or a family history of bowel cancer, coeliac disease or IBD — mention these to us

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This information is general and not a substitute for personalised medical advice. Please discuss any questions with your gastroenterologist or GP. If you develop severe symptoms, call 000 or go to your nearest emergency department.