This factsheet is about Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) consists of a number of symptoms. The most common symptoms of IBS are abdominal pain and abnormal bowel habits. IBS is the most common disorder of the digestive system and up to one third of the population experience symptoms. Women are slightly more affected than men and the usual age for patients to seek advice is between 20 and 40 years.

How does irritable bowel syndrome occur?

During digestion, the bowel squeezes its contents along our insides towards the anus. This process (peristalsis) is usually painless and we do not realise that it is happening unless there is an abnormal squeeze within the bowel or, for some reason, the intestine becomes more sensitive. In addition, patients with IBS seem to have greater sensitivity to the way that their intestines are moving, meaning they feel pain more easily. These changes can be quite painful.

How food (food bolus) moves along the gut


Causes of irritable bowel syndrome

We do not think that IBS has a single cause. There is a wide variety of reasons why patients develop the condition. However, the single most common trigger to the start of symptoms is following a bout of food poisoning or gastroenteritis. There does not seem to be a genetic cause and there appears to be many factors that can provoke symptoms. Some people find that stress makes their symptoms worse. In some people, eating irregularly or eating an abnormal diet may be responsible. Some drugs, particularly when taken long term for chronic conditions, can cause IBS type symptoms such as diarrhoea. Overall, there seems to be some interaction between the nervous system in the gut and brain, emotional state, the gut microbes and the immune system of the gut.


How is irritable bowel syndrome diagnosed?

The GP will want to rule out other diseases but will probably be able to make a diagnosis based on the described symptoms. Sometimes IBS symptoms can be caused by drugs you are taking for other conditions. It may be worth discussing this with your doctor to see if a drug switch can be made.

Further tests may include blood tests, which will be used to assess the following:

  • Whether anaemia is present
  • Liver and kidney function
  • Any signs of inflammation in the bowel
  • Whether coeliac disease may be the issue
  • Faecal Calprotectin: this is a stool test increasingly used to look for inflammation so the doctor is sure that symptoms are not caused by other bowel disease. The doctor can then be confident that the diagnosis is IBS.

The GP will want to rule out other diseases but will probably be able to make a diagnosis based on the described symptoms.


How can IBS affect you?

IBS is one of the most common reasons for a visit to the GP. As many as 1 in 8 people have symptoms of IBS at any one time. Once diagnosed, and given help most people can find effective ways of living with their IBS.

The most common symptoms of IBS are:

  • Abdominal pain and abnormal bowel habits
  • Wind, bloating and distension (a widening of the girth of the abdomen)
  • Pooing mucus
  • One third of IBS patients suffer from bouts of constipation. One third of IBS patients suffer from bouts of diarrhoea, others don’t fall into a single pattern.
  • Other symptoms include feeling tired, feeling sick, backache and bladder symptoms.

Many patients with IBS get crampy abdominal discomfort or pain, which comes and goes, and fluctuates with bowel function (typically easing after a bowel movement). Other common symptoms are wind, bloating and distension (a widening of the girth of the abdomen) and pooing mucus. Sometimes other symptoms might also occur, such as feeling tired, feeling sick, backache and bladder symptoms. Approximately one third of IBS patients suffer from bouts of constipation, one third suffer from bouts of diarrhoea and most other patients don’t fall into a single pattern. The form of IBS that seems to follow gastroenteritis often leads to the diarrhoea type. This is called post infectious IBS. Identifying these different types of IBS is important because treatments often work quite differently depending upon whether diarrhoea or constipation is the main problem. However we do know that the pattern of bowel movements can alter over time and this means that your treatment might need to change should your symptoms vary.

Symptoms that may be of concern

These symptoms are not usually associated with IBS but may be associated with other diseases. If you experience any of these, even if you have had IBS for some time, you should see your doctor as soon as possible:

  • A persistent change of bowel habit for 4 weeks or longer, especially if you are over the age of 40
  • Passing blood from the back passage
  • Unintentional weight loss of more than 2kg (4 pounds) over a short period of time
  • Diarrhoea waking you from sleep
  • A fever

The need to see a doctor is especially important if there is a family history of bowel disease (such as cancer, colitis or Crohn’s disease).

Lady holding a mug looking out of the window smiling

If you experience any symptoms that may be of concern, even if you have had IBS for some time, you should see your doctor as soon as possible.


What treatment is available for Irritable Bowel Syndrome (IBS)?

Dietary management

If a dietary cause is suspected your GP can give advice on simple first line dietary changes to try or may refer you to a dietitian. The dietitian will try to identify any foods that cause your IBS symptoms (trigger food). This may involve leaving out particular sorts of foods from the diet, to see whether these symptoms improve. The dietitian may suggest an ‘exclusion diet’, which will exclude a number of common ‘trigger’ foods from your diet. A particular form of this is the low FODMAP diet. If symptoms improve, individual items can then be added back into the diet until the specific trigger food or foods are identified. If you have a diagnosis of an eating disorder, or you have had one in the past, exclusion diets may not be the best treatment option for you. There are other non diet treatments than can be tried, instead.

If constipation is a symptom, then bulking agents such as natural oat or rice bran, bran containing cereals such as oats, wholegrain rice or isphagula husk (a natural laxative) are helpful. But some laxatives containing fibre or senna, whilst helping with constipation, may make pain a little worse in some people. Avoid adding additional wheat bran in your diet as this can make symptoms worse.

Drug therapy

Drugs to reduce bowel spasm have been used for many years. They are generally very safe and often worth trying. Most are available without a prescription and the pharmacist can advise. Unfortunately, they only benefit a relatively small number of patients. Laxatives can be prescribed for constipation by your GP or from the pharmacist whilst some patients benefit from treatment with peppermint oil or other over-the-counter medicines. Some patients find probiotics very helpful, but there is no specific prescribed preparation. It is rather a question of trial and error. Sometimes when pain is a major problem, small doses of drugs, which are used as antidepressants, such as amitriptyline, can be helpful. These can be useful in patients who have no signs of depression. There are also new classes of drugs that may be used if simpler treatments do not succeed.

New drugs are being developed, some of which may help patients whose main symptom is diarrhoea and others who tend to be constipated. Some of these newer agents are not yet available to doctors to prescribe but it does seem likely that a wider range of treatments will be available to patients with IBS in the near future.

Other treatments

Hypnotherapy and relaxation therapy: These have both been shown to be effective for some people but it is unclear whether they improve bowel symptoms. Hypnotherapy can be obtained through approved therapists who should be members of the British Association of Clinical and Academic Hypnotherapists.  Ask about a type of therapy called gut directed hypnotherapy. Your GP can advise on counselling, and some specialists believe that a psychological treatment called Cognitive Behavioural Therapy (CBT) can be useful.

How can I self-manage my irritable bowel syndrome?

Irritable bowel syndrome (IBS) is a condition where good self-management can make a huge difference to the symptoms experienced.

Identifying trigger foods

This may be done with a dietitian. Keeping a food diary together with a record of bowel symptoms. This may show which foods cause the most problems or whether there is some other pattern. Foods which commonly cause abdominal upset include wheat products, dairy products, onions, nuts and caffeine-containing drinks such as coffee, tea and cola. Some patients cannot digest lactose (the sugar in milk) and so develop wind and diarrhoea after taking large amounts of milk or dairy products, which can include cream, cheese, yoghurt and chocolate.

Healthy eating habits

Following healthy eating habits, avoiding trigger foods and eating regularly can bring about a significant improvement in symptoms.

Patient support

The IBS Network provides a unique self-care programme to support people living with irritable bowel syndrome. The programme is available to members, to work through at home, or in IBS support groups. To become a member go to the website.

Young couple buying fruit and vegetables at the supermarket


What to ask your doctor?

These are some useful questions you can ask your doctor:

  • Have I been fully checked for other bowel conditions?
  • Are there any medications that would be appropriate for me to take?
  • May I be referred to a dietitian?
  • Are there any IBS patient groups in my area?
  • Can I have a review regularly for my IBS? (See quality standard 4, in drop-down below).

NICE Guidelines for IBS:

The National Institute of Health and Care Excellence (NICE) provide guidelines that doctors can follow when diagnosing and treating people with IBS. NICE also produce Quality Standards for IBS and these standards show what good service provision should look like. There are four standards currently:

1. Considering that people should have had a diagnosis of inflammatory bowel disease ruled out before providing a diagnosis of IBS.

2. Giving a positive diagnosis depending on symptoms meeting the diagnosis criteria for IBS and not just based on a process of excluding other diagnosis. Testing that may be required is listed.

3. Adults getting a referral to a trained practitioner if symptoms continue after first line dietary advice (see the IBS guideline) has not been effective to manage symptoms and a restricted or exclusion diet is required. Please note the ONLY trained practitioners are dietitians registered with the HCPC. This standard can facilitate a referral to a dietitian for a low FODMAP diet.

4. Many people live with IBS longer term without knowing about new treatments. This standard is an opportunity for a person with IBS to discuss their symptoms and how these are managed with their healthcare professional. An appointment to review your IBS can be requested at a frequency agreed by the person and their healthcare professional, and can take the form that they feel is the most appropriate (such as attending the GP practice or a telephone conversation). Please note you have to request this from your doctor (usually your GP) it is not automatically provided. Please read more about the standards here.


Guts UK’s Priority Setting Partnership (PSP) into IBS

The purpose of a PSP is to identify and prioritise the unanswered questions for certain medical conditions, or areas of health.

The process of a PSP brings together patients, carers, doctors, nurses, scientists, researchers, dietitians and other health professionals, all with an equal voice. Together, they will decide the top ten research priorities for their condition. Learn more here.

IBS Research Register

The National Institute for Health and Care Excellence (NICE), the government agency tasked with developing guidelines on how best to manage conditions, published guidelines for IBS, which were subsequently updated in 2017. As part of those guidelines, NICE published a set of research recommendations for areas and questions where more information was needed and hence more studies were encouraged.

These questions included:

  • What is the clinical and cost effectiveness of low-dose antidepressants for treating IBS in primary care?
  • What is the clinical and cost effectiveness of computerised CBT (cognitive behavioural therapy) and mindfulness therapy for the management of IBS in adults?
  • What is the clinical and cost effectiveness of a low FODMAP diet (as well as issues around research for culturally specific foods)?

Research centres such as King’s College London (KCL) and Monash University have carried out research on the Low FODMAP Diet. The team at KCL have gathered evidence that the Low FODMAP Diet is effective in the short and long-term, broadly acceptable to patients and enables a nutritionally balanced diet. They have also provided evidence and practice guidance to assist health professionals in the delivery of the low FODMAP diet.

In the area of CBT, a large study from the University of Southampton has found that CBT delivered over the phone or via a website was more effective than usual treatment for refractory IBS (IBS where symptoms continue after 12 months despite receiving appropriate medication and lifestyle advice). Face-to-face CBT had been shown before to be effective in IBS but patients often found adherence difficult and its availability in the NHS was poor. These telephone or web-based alternative ways to deliver CBT are a promising addition to the treatment for IBS.

Research on IBS is carried out globally. A new registry called ContactME-IBS allows users to find out about IBS research and will also give users the opportunity to be matched to relevant IBS studies when they become available.

Register here for further information.


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