The main symptoms are abdominal pain or discomfort that is often relieved by passing wind or faeces, stomach bloating, and chronic diarrhoea or constipation (or alternating between the two).

These symptoms can be embarrassing, inconvenient and distressing. Fortunately, IBS does not cause permanent damage to the bowel and it does not cause other serious diseases like bowel cancer.

If you have IBS, then an episode can be triggered by an infection, stress, food intolerance, hormonal factors such as menstruation or particular medicines.

The exact cause of IBS is unknown. It’s probably due to many factors, including the nerves in the bowel being more sensitive than usual (allowing the person to feel sensations they wouldn’t normally feel), abnormal contractions in the bowel, chronic inflammation of the bowel and psychological factors.

Who develops IBS?

IBS develops in as many as 1 in 5 Australians at some point in their lifetime, and is twice as common in women as it is in men.

It often develops in the late teens or early 20s. Having a close relative with IBS may slightly increase your chance of having it.

How do I know if I have IBS?

The main feature of IBS is abdominal pain associated with a change in bowel habits.

Symptoms to look for include:

• recurring episodes of diarrhoea or constipation
• symptoms that alternate between diarrhoea and constipation
• bloating
• pain or discomfort that is relieved by passing wind or going to the toilet
• symptoms are more common in women and may be worse around menstruation or at times of stress

IBS does not cause bleeding from the back passage.

IBS is usually diagnosed based on your symptoms and your medical history. There is no medical test that can be used to confirm a diagnosis, although tests (such as a blood test or a colonoscopy) may be required to rule out other conditions.

Check your symptoms with healthdirect’s Symptom Checker to get advice on when to seek medical attention.

This is particularly necessary if you are over 40 when you develop symptoms, if you have a family history of bowel cancer, or if there are other signs or symptoms which suggest another condition could be causing your symptoms.

How is IBS treated?

It is important to have a doctor who will carefully explain your condition, answer your questions, and work with you to develop a management plan suitable for your individual needs.

Managing IBS may include one or all of the following:

• reassurance that the symptoms are not due to cancer
• changing your lifestyle and diet
• reviewing medication that might aggravate diarrhoea or constipation
• a good healthy diet, including dietary fibre

Some people choose to take medicines to treat their symptoms when they flare up. These may include:

• anti-diarrhoeal medicines
• painkillers
• constipation treatments
• antispasmodics (to ease cramping)
• antidepressants (which are used to treat pain and depression)

Physiotherapy can be helpful in some cases to teach you how to use your muscles to control your bowel function more effectively.

Your doctor will also work with you to discover if psychological issues like anxiety, depression or stress are a problem for you. In some cases it may be beneficial to see a psychologist or counsellor who can teach you strategies for dealing with these issues and for coping with IBS.

For more information about medicines and IBS, visit the NPS website.

Changing your diet

There is no ‘one-size-fits-all’ diet for IBS. However, dietary changes can often relieve IBS symptoms.

It may help to keep a food diary so you can identify any foods that make your symptoms worse.

It can also help to modify the amount and type of fibre in your diet:

• If you have IBS with constipation, it can help to eat more soluble fibre and drink more water.
• If you have IBS with diarrhoea, it can help to cut down on insoluble fibre.

In some cases, avoiding a particular food or food group might help — examples include gluten, caffeine, alcohol, spicy foods, high fat foods or foods that cause excessive bloating such as beans, lentils or certain vegetables.

Australian researchers have recently developed a special diet that may help control IBS symptoms in some people. It’s called the FODMAP diet, and it involves restricting your intake of certain dietary carbohydrates (sugars) that are poorly absorbed by the bowel. For more information about the FODMAP diet, visit the Monash University website.

Before making any major changes to your diet it is a good idea to talk to your doctor or a dietitian.

Finding help

If IBS symptoms are getting you down, talk to your doctor or contact a support organisation.