In short: Irritable bowel syndrome (IBS) is a common, long-term condition affecting how the gut works. It typically causes tummy pain or cramping, bloating and changes in bowel habit (diarrhoea, constipation or both) that come and go. There is no single test for IBS, so a clinician makes the diagnosis from your symptoms after simple tests have ruled out other conditions. Diet, lifestyle changes, medicines for specific symptoms and psychological therapies can all help.

This guide, written by a Ready Health prescribing pharmacist, explains how IBS is recognised and managed in the UK, based on NICE guideline CG61.

What is IBS?

IBS is a disorder of gut–brain interaction. The bowel looks normal and is not damaged, but it is more sensitive and may move food along too quickly or too slowly. Symptoms vary from person to person and often flare with stress, certain foods or hormonal changes. IBS does not lead to bowel cancer or inflammatory bowel disease, but it can have a real impact on daily life.

What are the symptoms of IBS?

abdominal pain or cramping, often eased by opening your bowels
bloating or a swollen tummy
diarrhoea, constipation, or alternating between the two
urgency, straining, or a feeling of not fully emptying your bowels
passing mucus
symptoms that worsen after eating

Some people also experience tiredness, nausea, backache or bladder symptoms.

How is IBS diagnosed?

NICE suggests considering IBS if you have had abdominal pain or discomfort, bloating or a change in bowel habit for at least six months. A diagnosis is more likely if the pain is relieved by opening your bowels or linked to a change in how often you go or what your stools look like, alongside at least two of: straining, urgency or incomplete emptying; bloating or tension in the abdomen; symptoms worse after eating; or passing mucus.

Before confirming IBS, a clinician will usually arrange:

a full blood count (to check for anaemia)
inflammatory markers (CRP or ESR)
a coeliac disease antibody test
sometimes a stool test called faecal calprotectin, to help rule out inflammatory bowel disease, especially if diarrhoea is a main symptom

Additional tests such as colonoscopy are not routinely needed when symptoms fit IBS and there are no warning signs.

When could it be something other than IBS?

See a doctor promptly if you have any of the following, as they need further investigation:

unexplained weight loss
bleeding from the bottom or blood in your stools
a lasting change in bowel habit if you are over 60
a lump in your tummy or back passage
anaemia, or a family history of bowel or ovarian cancer
in women, especially over 50, persistent bloating, feeling full quickly or pelvic pain – these can be signs of ovarian cancer and a CA125 blood test may be advised

How is IBS treated?

Diet and lifestyle

eat regular meals and take time to eat; avoid skipping meals or eating late at night
drink plenty of fluids, mainly water, and limit caffeine, alcohol and fizzy drinks
adjust fibre: some people improve by reducing insoluble fibre (bran), while oats or linseeds may help wind and bloating
limit fresh fruit to around three portions a day and reduce sugar-free sweeteners (sorbitol) if diarrhoea is a problem
keep physically active and find ways to manage stress
if you try a probiotic, take it for at least four weeks and stop if there is no benefit

If these steps are not enough, a low FODMAP diet may help, but it should be done with support from a dietitian because it is restrictive.

Medicines for specific symptoms

A pharmacist or prescriber may suggest antispasmodics for cramping, laxatives for constipation (NICE advises avoiding lactulose in IBS) or loperamide for diarrhoea. If symptoms continue, a prescriber may consider a low-dose antidepressant, which can reduce gut pain signals. A prescriber decides which option is suitable for you.

Psychological therapies

For people whose symptoms have not improved after 12 months of other treatment, NICE recommends considering cognitive behavioural therapy (CBT), hypnotherapy or other psychological approaches, which can help with the gut–brain connection.

Frequently asked questions

Is IBS serious?

IBS does not damage the bowel or cause cancer, but it can significantly affect quality of life. New or changing symptoms should always be checked.

Can IBS be cured?

There is no cure, but most people find a combination of diet, lifestyle and targeted treatment controls their symptoms well.

Can stress cause IBS?

Stress does not cause IBS on its own, but it can trigger or worsen flare-ups because of the close link between the brain and the gut.

Should I cut out gluten or dairy?

Not without advice. Get tested for coeliac disease before reducing gluten, as cutting it out first can make the test unreliable.

Key takeaways

IBS causes recurring tummy pain, bloating and changes in bowel habit without damaging the gut.
Diagnosis is based on symptoms plus simple blood tests to exclude other conditions.
Warning signs such as bleeding, weight loss or new symptoms over 60 need prompt medical review.
Diet changes, symptom-targeted medicines and psychological therapies can all help.

Sources and further reading

Last reviewed: October 2026 by Shamir Patel, Independent Prescribing Pharmacist, Ready Health. This article is general information and does not replace advice from your own clinician.

Struggling with ongoing gut symptoms? Ready Health in Standish, Wigan offers private GP appointments and blood tests to help investigate your symptoms and plan next steps. Book a GP appointment.