Irritable bowel syndrome


Irritable bowel syndrome


Irritable bowel syndrome (IBS) is a common, long-term condition of the digestive system. It can cause bouts of stomach cramps, bloating, diarrhoea and/or constipation.

The symptoms vary between individuals and affect some people more severely than others. They tend to come and go in periods lasting a few days to a few months at a time, often during times of stress or after eating certain foods.

You may find that some of symptoms improve after having a poo.

IBS is thought to affect up to one in five people at some point in their life, and it usually first develops when a person is between 20 and 30 years of age. Around twice as many women are affected as men.

The condition is often life-long, although it may improve over several years.

When to see your GP

See your GP if you think you have IBS symptoms, so they can try to determine the cause.

Your GP may be able to identify IBS based on your symptoms, although blood tests may be needed to rule out other conditions.

What causes IBS?

The exact cause of IBS is unknown, but most experts think that it's related to increased sensitivity of the gut and problems digesting food.

These problems may mean that you are more sensitive to pain coming from your gut, and you may become constipated or have diarrhoea because your food passes through your gut either too slowly or too quickly.

Psychological factors such as stress may also play a part in IBS.

How IBS is treated

There is no cure for IBS, but the symptoms can often be managed by making changes to your diet and lifestyle.

For example, it may help to:

identify and avoid foods or drinks that trigger your symptoms

alter the amount of fibre in your diet

exercise regularly

reduce your stress levels

Medication is sometimes prescribed for people with IBS to treat the individual symptoms they experience.

Living with IBS

IBS is unpredictable. You may go for many months without any symptoms, then have a sudden flare-up.

The condition can also be painful and debilitating, which can have a negative impact on your quality of life and emotional state. Many people with IBS will experience feelings of depression and anxiety, at some point. 

Speak to your GP if you have feelings of depression or anxiety that are affecting your daily life. These problems rarely improve without treatment and your GP can recommend treatments such asantidepressants or cognitive behavioural therapy (CBT), which can help you cope with IBS, as well as directly treating the condition.

With appropriate medical and psychological treatment, you should be able to live a normal, full and active life with IBS. 

IBS does not pose a serious threat to your physical health and does not increase your chances of developing cancer or other bowel-related conditions.

Symptoms of IBS 

The symptoms of IBS are usually worse after eating and tend to come and go in episodes.

Most people have flare-ups of symptoms that last a few days. After this time, the symptoms usually improve, but may not disappear completely.

In some people, the symptoms seem to be triggered by something they have had to eat or drink. 

Main symptoms

The most common symptoms of IBS are:

abdominal (stomach) pain and cramping, which may be relieved by having a poo

a change in your bowel habits – such as diarrhoea, constipation, or sometimes both

bloating and swelling of your stomach  

excessive wind (flatulence)

occasionally experiencing an urgent need to go to the toilet

a feeling that you have not fully emptied your bowels after going to the toilet 

passing mucus from your bottom 

Additional problems

In addition to the main symptoms described above, some people with IBS experience a number of other problems. These can include:

a lack of energy (lethargy)

feeling sick


bladder problems (such as needing to wake up to urinate at night, experiencing an urgent need to urinate and difficulty fully emptying the bladder)

pain during sex (dyspareunia)


The symptoms of IBS can also have a significant impact on a person's day-to-day life and can have a deep psychological impact. As a result, many people with the condition have feelings of depression andanxiety.

When to see your GP

You should see your GP if you think you have IBS symptoms, so they can try to identify the cause.

They can often do this by asking about your symptoms, although further tests are occasionally needed to rule out other conditions.

You should also visit your GP if you are feeling anxious or depressed. These problems rarely improve without treatment and could make your IBS symptoms worse.

If you have other symptoms – including unexplained weight loss, a swelling or lump in your stomach or bottom, bleeding from your bottom, or signs of anaemia – you should see your GP right away, as these can sometimes be a sign of a potentially more serious condition.

Causes of IBS 

The exact cause of irritable bowel syndrome (IBS) is unknown, but most experts think that it's related to problems with digestion and increased sensitivity of the gut.

Many causes have been suggested – including inflammation, infections and certain diets – but none have been proven to directly lead to IBS.

Problems with digestion

Your body usually moves food through your digestive system by squeezing and relaxing the muscles of the intestines in a rhythmic way.

However, in IBS it's thought that this process is altered, resulting in food moving through your digestive system either too quickly or too slowly.

If food moves through your digestive system too quickly it causes diarrhoea, because your digestive system does not have enough time to absorb water from the food.

If food moves through your digestive system too slowly it causes constipation, as too much water is absorbed, making your stools hard and difficult to pass.

It may be that food does not pass through the digestive systems of people with IBS properly because the signals that travel back and forth from the brain to the gut are disrupted in some way.

An increase in serotonin levels, which can occur after eating certain foods or during times of stress, is also thought to affect the normal functioning of the gut.

Increased gut sensitivity

Many sensations in the body come from your digestive system. For example, nerves in your digestive system relay signals to your brain to let you know if you are hungry or full, or if you need to go to the toilet.

Some experts think that people with IBS may be oversensitive to the digestive nerve signals. This means mild indigestion that is barely noticeable in most people becomes distressing abdominal (stomach) pain in those with IBS.

Psychological factors

There is also some evidence to suggest that psychological factors play an important role in IBS.

However, this does not mean that IBS is "all in the mind", because symptoms are very real. Intense emotional states such as stress and anxiety can trigger chemical changes that interfere with the normal workings of the digestive system.

This does not just happen in people with IBS. Many people who have never had IBS before can have a sudden change in bowel habits when faced with a stressful situation, such as an important exam or job interview.

Some people with IBS have experienced a traumatic event, usually during their childhood, such as abuse, neglect, a serious childhood illness or bereavement.

It is possible that these types of difficult experiences in your past may make you more sensitive to stress and the symptoms of pain and discomfort.

IBS triggers

Certain foods and drinks can trigger the symptoms of IBS. Triggers vary from person to person, but common ones include:


fizzy drinks


drinks that contain caffeine – such as tea, coffee or cola

processed snacks – such as crisps and biscuits

fatty or fried food

Keeping a food diary may be a useful way of identifying possible triggers in your diet.

Stress is another common trigger of IBS symptoms. Therefore, findingways to manage stressful situations is an important part of treating the condition.

Diagnosing IBS 

There are no specific tests for IBS, as it does not cause any obvious detectable abnormalities in your digestive system.

In most cases, a diagnosis will be based on whether you have typical symptoms of IBS.

Your GP will consider assessing you for IBS if you have had any of the following symptoms for at least six months:

abdominal (stomach) pain or discomfort


a change in bowel habit – such as passing stools more frequently,diarrhoea and/or constipation

A diagnosis of IBS will then be considered if you have stomach pain or discomfort that is either relieved by passing stools, or is associated with a need to go to the toilet frequently or a change in the consistency of your stools. 

This should be accompanied by at least two of the following four symptoms:

a change in how you pass stools – such as needing to strain, feeling a sense of urgency or feeling you have not emptied your bowels properly

bloating, hardness or tension in your stomach

your symptoms get worse after eating

passing mucus from your back passage

Ruling out other conditions

Many cases of IBS can be diagnosed based on your symptoms alone, although sometimes further tests may be needed to check for other possible causes.

For example, your GP may arrange blood tests to rule out other conditions that cause similar symptoms, such as an infection or coeliac disease (a digestive condition where a person has an adverse reaction to gluten).

A sample of your stools will also often be tested for the presence of a substance called calprotectin. This substance is produced by the gut when it is inflamed, and its presence in your stools could mean your symptoms are being caused by inflammatory bowel disease (IBD).

Investigating 'red flags'

Further tests will be needed when you have certain "red flag" symptoms that indicate you may have a potentially more serious condition, such as cancer. These symptoms include:

unexplained weight loss

a swelling or lump in your stomach or back passage

bleeding from your back passage (rectum)


Further testing may also be recommended if you have a family history of bowel cancer or ovarian cancer, or if you are over 60 years of age and have had a change in your bowel habits that has lasted for more than six weeks.

In these cases, your doctor may recommend having a colonoscopy to check for abnormalities in your gut. This is where your rectum and large bowel (colon) are examined using an endoscope, which is inserted into your rectum.

Treating IBS 

The symptoms of irritable bowel syndrome (IBS) can often be managed by changing your diet and lifestyle, and understanding the nature of the condition.

In some cases, medication or psychological treatments may also be helpful.

IBS-friendly diet

Changing your diet will play an important part in controlling your symptoms of IBS. However, there is no "one size fits all" diet for people with the condition. The diet that works best for you will depend on your symptoms and how you react to different foods.

It may be helpful to keep a food diary and record whether certain foods make your symptoms better or worse. You can then avoid foods that trigger your symptoms. However, it's important to remember that these foods will not necessarily need to be avoided for life.


People with IBS are often advised to modify the amount of fibre in their diet. There are two main types of fibre: soluble fibre (which the body can digest) and insoluble fibre (which the body cannot digest).

Foods that contain soluble fibre include:




fruit – such as bananas and apples

root vegetables – such as carrots and potatoes

golden linseeds

Foods that contain insoluble fibre include:

wholegrain bread



nuts and seeds (except golden linseeds)

If you have diarrhoea, you may find it helps to cut down on the insoluble fibre you eat. It may also help to avoid the skin, pith and pips from fruit and vegetables.

If you have constipation, increasing the amount of soluble fibre in your diet and the amount of water you drink can help.

Your GP may be able to advise on what your recommended fibre intake should be.

Low FODMAP diet

If you experience persistent or frequent bloating, a special diet called the low FODMAP diet can be effective.

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. This means they start to ferment in the gut relatively quickly, and the gases released during this process can lead to bloating.

A low FODMAP diet essentially involves restricting your intake of various foods that are high in FODMAPs, such as some fruits and vegetables, animal milk, wheat products and beans.

If you want to try the low FODMAP diet, it’s best to do so under the guidance of a professional dietitian, who can ensure your diet is still healthy and balanced. You can ask your GP or specialist to refer you.

General eating tips

Your IBS symptoms may also improve by:

having regular meals and taking your time when eating

not missing meals or leaving long gaps between eating

drinking at least eight cups of fluid a day – particularly water and other non-caffeinated drinks, such as herbal tea

restricting your tea and coffee intake to a maximum of three cups a day

reducing the amount of alcohol and fizzy drinks you drink

reducing your intake of resistant starch (starch that resists digestion in the small intestine and reaches the large intestine intact), which is often found in processed or re-cooked foods

limiting fresh fruit to three portions a day – a suitable portion would be half a grapefruit or an apple

if you have diarrhoea, avoiding sorbitol, an artificial sweetener found in sugar-free sweets, including chewing gum and drinks, and in some diabetic and slimming products

if you have wind (flatulence) and bloating, it may help to eat oats (such as oat-based breakfast cereal or porridge) and linseeds (up to one tablespoon a day)


Many people find that exercise helps to relieve the symptoms of IBS. Your GP can advise you on the type of exercise that is suitable for you.

Aim to do a minimum of 150 minutes of moderate-intensity aerobic activity, such as cycling or fast walking, every week.

The exercise should be strenuous enough to increase your heart and breathing rates.

Reducing stress

Reducing your stress levels may also reduce the frequency and severity of your IBS symptoms. Some ways to help relieve stress include:

relaxation techniques – such as meditation or breathing exercises

physical activities – such as yoga, pilates or tai chi

regular exercise – such as walking, running or swimming

If you are particularly stressed, you may benefit from a talking therapy, such as stress counselling or cognitive behavioural therapy (CBT).


Probiotics are dietary supplements that product manufacturers claim can help improve digestive health. They contain so-called "friendly bacteria" that can supposedly restore the natural balance of your gut bacteria when it has been disrupted.

Some people find taking probiotics regularly helps to relieve the symptoms of IBS. However, there is a little evidence to support this, and it is unclear exactly how much of a benefit probiotics offer and which types are most effective.

If you want to try a probiotic product, you should take it for at least four weeks to see if your symptoms improve, and you should follow the manufacturer's recommendations regarding dosage.


A number of different medications can be used to help treat IBS, including:

antispasmodics – which help reduce abdominal (stomach) pain and cramping

laxatives – which can help relieve constipation

antimotility medicines – which can help relieve diarrhoea

low-dose antidepressants – which were originally designed to treat depression, but can also help reduce stomach pain and cramping independent of any antidepressant effect

These medications are discussed in more detail below. 


Antispasmodics work by helping to relax the muscles in your digestive system. Examples of antispasmodic medicines include mebeverine andtherapeutic peppermint oil.

Side effects associated with antispasmodics are rare. However, people taking peppermint oil may have occasional heartburn and irritation on the skin around their bottom.


Bulk-forming laxatives are usually recommended for people with IBS-related constipation. They make your stools softer, which means they are easier to pass.

It's important to drink plenty of fluids while using a bulk-forming laxative. This will help prevent the laxative from causing an obstruction in your digestive system.

Start on a low dose and then, if necessary, increase it every few days until one or two soft stools are produced every one or two days. Do not take a bulk-forming laxative just before you go to bed.

Side effects associated with taking laxatives can include bloating and wind. However, if you increase your dose gradually, you should have few, if any, side effects.

Antimotility medicines

The antimotility medicine loperamide is usually recommended for IBS-related diarrhoea.

Loperamide works by slowing contractions of muscles in the bowel, which slows down the speed at which food passes through your digestive system. This allows more time for your stools to harden and solidify.

Side effects of loperamide can include stomach cramps and bloating,dizziness, drowsiness and rashes.


Two types of antidepressants are used to treat IBS – tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs).

TCAs, such as amitriptyline, are usually recommended when antispasmodic medicines have not been able to control the symptoms of pain and cramping. They work by preventing signals being sent to and from the nerves in your digestive system.

However, TCAs will only start to provide relief after three to four weeks, as your body gets used to the medication.

Side effects of TCAs can include a dry mouth, constipation, blurred vision and drowsiness. These side effects should improve within a few days of starting the medication. Tell your GP if the side effects become a problem – they may prescribe another type of antidepressant.

SSRIs are an alternative type of antidepressant. Examples of SSRIs that are used to treat IBS include citalopram, fluoxetine and paroxetine.

Common side effects of SSRIs include blurred vision, dizziness and diarrhoea or constipation.

Psychological treatments

If your IBS symptoms are still causing problems after 12 months of treatment, your GP may refer you for a type of therapy known as a psychological intervention.

There are several different types of psychological therapy. They all involve teaching you techniques to help you control your condition better, and there is good evidence to suggest they may help some people with IBS.

Psychological treatments that may be offered to people with IBS include:

psychotherapy – a type of therapy that involves talking to a trained therapist to help you to look deeper into your problems and worries

cognitive behavioural therapy (CBT) – a type of psychotherapy that involves examining how beliefs and thoughts are linked to behaviour and feelings, and teaches ways to alter your behaviour and way of thinking to help you cope with your situation

hypnotherapy– where hypnosis is used to change your unconscious mind's attitude towards your symptoms

Complementary therapies

Some people claim therapies such as acupuncture and reflexology can help people with IBS. However, there is no medical evidence to suggest their effectiveness, and they are not recommended.