Irritable Bowel Syndrome
Recurring tummy pain linked to bowel motions, with diarrhoea, constipation or both, often with bloating. It affects about 1 in 10 people. It is a real problem with how the gut and brain communicate, and doesn’t damage the bowel or cause cancer. Your GP will usually check bloods, and sometimes a stool test, to rule out other causes such as coeliac disease.
Treatment options
Ratings show how strong the research is.
- Strong evidenceLow-dose amitriptylineA small dose at night calms gut nerves (not as an antidepressant). In a large 2023 UK GP trial it nearly doubled the chance of improvement. Allow 3 to 4 weeks.
- Moderate evidenceLow FODMAP diet, with a dietitianCut out certain fermentable carbohydrates for 2 to 6 weeks, then reintroduce them to find your triggers. Helps more than half of people. Don’t stay on the strict phase long-term.
- Moderate evidenceSoluble fibre (psyllium)Start with a small dose and build up slowly. Helps both constipation and diarrhoea. Bran (insoluble fibre) can make it worse.
- Moderate evidencePeppermint oil capsulesEnteric-coated capsules can ease pain and bloating. May worsen reflux.
- Moderate evidenceGut-directed hypnotherapy or CBTPsychological therapies that retrain gut-brain signals. In a Monash trial, hypnotherapy worked as well as the low FODMAP diet. Available in person, online or by app.
- Moderate evidenceMedicines for main symptomsLoperamide for diarrhoea, or a macrogol laxative for constipation. Ask your pharmacist.
- Limited evidenceProbioticsSome people benefit. Try one for 4 weeks and stop if no change.
- Not recommendedFood intolerance blood (IgG) testsNot reliable for IBS and can lead to unnecessary diets.
What you can do
- Eat regular meals and don’t rush them. Limit alcohol, caffeine, fizzy drinks and sugar-free sweeteners (sorbitol, mannitol).
- Keep a food and symptom diary for 2 weeks to bring to appointments.
- Exercise regularly: even walking or yoga eases symptoms.
- Don’t cut out gluten or whole food groups without advice: get tested for coeliac disease first.
See your GP if
- Symptoms began after age 50, or have recently changed
- Blood in your bowel motions, or black stools
- Weight loss you can’t explain, or diarrhoea waking you at night
- A family history of bowel cancer, coeliac disease or inflammatory bowel disease
Go to the emergency department for severe or constant tummy pain, vomiting, high fever, or heavy bleeding from the bottom.
Evidence and more information
- Healthdirect: Irritable bowel syndrome
- Monash University: Hypnotherapy on par with low FODMAP diet
- University of Bristol: Amitriptyline helps IBS (ATLANTIS trial)
- NICE: Irritable bowel syndrome in adults
maladywise.com/ibs/