What is irritable bowel syndrome (IBS)?

Irritable bowel syndrome (IBS) is a common condition where you experience symptoms related to your digestive system. This is sometimes linked to certain foods, lifestyle habits and stress levels or mood. IBS affects around 3 out of every 10 people. Females are more likely than males to be affected.

In IBS, medical investigations such as blood tests, endoscopy and imaging tests don’t show any abnormalities. IBS is a different disease from inflammatory bowel disease (IBD, including Crohn’s disease and ulcerative colitis).

IBS symptoms can have a huge impact on your quality of life.

What are the symptoms of irritable bowel syndrome?

Some key symptoms of IBS include:

• abdominal pain or discomfort
• stomach bloating and wind
• chronic diarrhoea or constipation, or alternating between the two

You may feel your bowel movement was incomplete (even after a poo) and nausea.

Often your pain can be relieved by passing wind or faeces.

What causes irritable bowel syndrome?

While the exact cause of IBS is not clear, some common IBS triggers include diet, stress, infection and medicines.

You may find that some foods make your symptoms worse, but these 'trigger foods' differ from one person to the next.

Your IBS symptoms might have started after an infection such as gastroenteritis (‘gastro’). Other triggers include a period of increased stress, or taking a medicine. Some antibiotics, antacids and pain medicines can affect your symptoms.

See your doctor or pharmacist to check whether these may have triggered your symptoms, and what treatment best suits your condition.

When should I see my doctor?

It is important to see your doctor if you develop symptoms. They will check for other conditions before diagnosing you with IBS.

If you have IBS you should see your doctor if:

• you are concerned about your symptoms, and if they are severe or ongoing
• you notice any blood in your stools
• you have unexplained or unintentional weight loss
• you have a fever or severe diarrhoea

IBS does not cause these symptoms, so it is important that a health professional assess you to exclude a more serious condition.

How is irritable bowel syndrome diagnosed?

IBS is a diagnosis of exclusion. This means that your doctor can only diagnose IBS after ruling out other conditions that could be causing your symptoms. These could include:

• infections
• inflammatory bowel disease (IBD)
• coeliac disease
• food allergies
• bowel cancer

Your doctor may rule out these conditions by referring you for investigations such as:

• blood tests
• stool tests
• endoscopic investigations such as sigmoidoscopy or colonoscopy

If you’ve been experiencing IBS symptoms for at least 6 months and these tests are all normal, then your doctor may diagnose you with IBS.

How is irritable bowel syndrome treated?

There are a wide range of treatment approaches available for IBS. Diet and lifestyle changes are often the best long term strategy to relieve your symptoms. A dietitian can make sure you don’t miss out on any key nutrients while you are trying to identify and exclude foods that trigger your IBS.

Other treatment options that may help you include:

• prescription medicines and over-the-counter medicines, including anti-depressants, antibiotics, laxatives and anti-diarrhoeal medicines
• herbal remedies such as peppermint oil
• nutritional supplements such as fibre and probiotics
• physical activity such as yoga
• psychological therapies such as cognitive behavioural therapy (CBT) and hypnosis

How can I reduce my IBS symptoms?

Your IBS symptoms can often be reduced by adopting healthy lifestyle habits including dietary changes.

Dietary fibre adds bulk to your stools allowing them to retain enough water to be soft and easy to pass. Your IBS symptoms may be worse if you don’t eat enough fibre or if you eat too much fibre. Sources of dietary fibre include fruits, vegetables and high fibre cereal. It’s best to slowly increase your dietary fibre intake up to the recommended daily intake of 25-30g per day. This is to avoid bloating and wind-related discomfort. If this is difficult for you, ask your pharmacist for a soluble fibre supplement, such as psyllium.

Some foods and drinks commonly trigger IBS, so try to reduce your intake of the following to see if this helps:

• gas-producing foods, such as onion, cabbage, Brussels sprouts, dried beans, lentils and cauliflower
• foods with lactose (milk sugar) such as milk, ice cream and some yoghurts
• alcoholic drinks
• artificial sweeteners in food and drink, such as aspartame, sorbitol and mannitol

A dietitian can help you identify your individual triggers and can work with you to create a balanced diet that suits you.

Sometimes, a low FODMAP diet may be recommended for you. FODMAP is short for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. These are the chemical names for different sugars that are poorly absorbed in the gut. For some people these can trigger symptoms of IBS.

Other strategies that may reduce your IBS symptoms include:

• physiotherapy to help address pelvic floor dysfunction
• hypnotherapy
• relaxation exercises

Complications of IBS

IBS is often a mild condition that can be well-managed by diet and other lifestyle improvements, but it may significantly impact your quality of life and can be stressful to manage. Some people develop depression and anxiety, migraine, fibromyalgia and/or chronic fatigue syndrome.

If IBS is causing you to feel down, anxious or upset, there are IBS-specific psychological support services. Talk to your GP about whether they are right for you.

People with IBS have a small risk of faecal incontinence. The Continence Foundation of Australia can help with strategies where this is due to constipation or diarrhoea. Call their toll-free helpline for advice on 1800 33 00 66.

Resources and support

For more information and support, try these resources:

• Monash University FODMAPs and Irritable Bowel Syndrome.
• The Continence Foundation of Australia — National Continence Helpline.
• Dietitians Australia — A guide to IBS.

Other languages

Do you prefer to read in a language other than English? The Continence Foundation of Australia has fact sheets on healthy diet and bowels. These are translated into over 25 different languages.