Irritable Bowel Syndrome (IBS)

What is IBS?

Irritable bowel syndrome (IBS) is a chronic digestive system disorder. It is very common – up to one in five people experience symptoms of IBS.

The most common symptom of IBS is abdominal pain together with changes in bowel habits (constipation and/or diarrhoea).

What are the symptoms of IBS?

Symptoms of IBS vary from one person to the next. Some people have very mild symptoms, while others are severely affected.

The symptoms of constipation are:

  • bouts of crampy abdominal pain – may worsen with stress and improve after passing a bowel motion
  • diarrhoea or constipation or alternating diarrhoea and constipation
  • mucus on/in the stools
  • bloating, gas and belching.

Symptoms tend to come and go in periods lasting a few days to a few months.

None of the symptoms of IBS occur only with IBS. It’s important to report symptoms to your doctor so you can get the right diagnosis and the right treatment.

What causes IBS?

The exact cause of IBS is unknown. Some of the suggested causes of IBS include:

  • abnormal contractions or spasms of the intestines
  • a complication after a severe gut infection (e.g. Salmonella)
  • anxiety and stress
  • food intolerances (e.g. lactose)
  • general diet (e.g. low fibre, spicy foods)
  • increased sensitivity of the nerves of the intestines.

How is IBS diagnosed?

There are no specific tests for IBS. The diagnosis is usually based on symptoms.

Sometimes your doctor will suggest ruling out other conditions before making a diagnosis of IBS. Other conditions with similar symptoms to IBS are:

  • malabsorption (abnormal absorption of nutrients),
  • inflammatory bowel disease (such as ulcerative colitis and Crohn’s disease)
  • coeliac disease
  • microscopic colitis (uncommon diseases associated with intestinal inflammation).

Tests for these other conditions include blood tests, faecal tests and colonoscopy.

How is IBS treated?

There is no one single treatment the suits all people. You may need to try several treatments before you find what works for you.

During treatment, you will need to watch your symptoms, daily bowel habits and other things that may affect your bowels. This helps identify factors that worsen and improve your symptoms.

Diet Changes

Changing your diet is an important part of controlling your symptoms. Your IBS specialist can help you work out what foods to eat and what to avoid.
One diet that is commonly tried is the low FODMAP diet. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. These are types of carbohydrates that aren’t easily broken down and absorbed by the gut. Instead, they ferment and release gases released into the gut that can lead to bloating.

If you want to try the low FODMAP diet or any other diet, it’s best to do so with the guidance of your IBS specialist.


Many people with IBS say that exercise helps their symptoms. Ideally, you want to do exercise that is strenuous enough to increase your heart and breathing rates.

Stress reduction

By reducing your stress and anxiety levels, you can reduce the severity and frequency of your IBS symptoms.

The best way to reduce stress will depend on your situation and what you find relaxing. Some people find counselling helpful, others like mediation, yoga, tai chi or even swimming are good for stress.


Probiotics are ‘friendly bacteria’ that are taken to restore the balance of your gut bacteria.

Some people find probiotics helpful, some people don’t. If you want to try them, you should take them daily for at least 4 weeks to see if your symptoms improve.


Various medications have been used to help treat IBS. These include:

  • antispasmodics – these reduce pain due to cramping
  • laxatives – to help relieve constipation
  • anti-motility medicine – to slow down the speed of food moving through your gut, which reduces diarrhoea
  • antidepressants – these work by changing the nerve activity in the gut.
Psychological treatments

As well as helping with stress management, psychological therapies can help some people control their IBS symptoms.

Your IBS specialist can help you find the treatments that work best for you.