The Causes of IBS


What is Irritable Bowel Syndrome?

Irritable Bowel Syndrome (IBS) refers to shifting abdominal pain with alternating constipation and diarrhoea. This is sometimes described as irregular or disturbed bowel function. In earlier times it was called 'spastic colon'. One of these symptoms alone may be the prominent one which compels a patient to seek treatment. There may be pain with either constipation or diarrhoea, but more commonly, IBS refers to this alternation between constipation and diarrhoea, where the pain is shifting. While the pain is often confined to one quadrant of the abdomen, it is not always in precisely the same location. Pain relief from passing flatus is found only in some patients.    

Diagnostic Features of IBS

IBS has recurrent abdominal pain plus two or more of: 

  • Pain better from defecation
  • Altered stool at the onset of pain
  • Abdominal bloating
  • Increased or decreased stools at the onset of pain
  • A ‘never completely empty’ sensation after passing stool
  • Passing mucus from the rectum
  • Morning cluster of motions
  • Constipation alternating with diarrhoea.

Other symptoms reported by patients with IBS: 

  • Fatigue (some IBS patients also have Chronic Fatigue Syndrome)
  • Nausea
  • Unexplained insomnia or disturbed sleep patterns
  • Susceptibility to colds, flus, sinusitis or post-nasal drip
  • Headaches
  • Allergic sensitivity
  • Restless leg syndrome
  • Gastric reflux
  • Crawling skin. 

Patients are sometimes diagnosed with IBS even though they do not have the above specific symptoms. In practice, IBS has become a generic  term for the presence of abdominal pain with variable bowel habits, once pathology tests have excluded other causes. Some of the ‘red flag’ symptoms in abdominal pain are listed below. With the rare exception of weight loss and fever (See Category 1 IBS), the symptoms below are not IBS and always require further evaluation: 

  • Weight loss
  • Blood in stools
  • Anaemia
  • Fever.

If the patient is over 50 and presents with altered bowel function, medical evaluation is always recommended.

It is also helpful, at least from a treatment perspective, to classify IBS as either constipation- or diarrhoea-dominant, since this will greatly affect the treatment plan.

When patients present for treatment at our clinic, many have already had a normal colonoscopy to exclude pathology. IBS is therefore considered to be a functional disturbance rather than a pathology, and is frequently a diagnosis made by exclusion of more serious bowel diseases.

Lifestyle Factors in IBS

Lifestyle factors may include: 

  • Stress
  • Excessive use of caffeine
  • Inadequate water intake
  • Inadequate sleep
  • Long working hours without finding time for toileting
  • Poor nutrition
  • Lack of exercise
  • Eating meals too quickly (thus swallowing air).


IBS is often stress related, but so are any other functional illnesses, such as migraines or period pain. While it is easy to dismiss IBS as just ‘stress’, in some cases emotional factors are clearly causative. A patient’s symptoms may disappear on weekends or holidays. A stressful work environment may be the only identifiable cause of symptoms. Therefore, one might then conclude that the IBS is a stress related functional disturbance. One specialist IBS clinic claims that 51% of female IBS patients reported a past history of life threatening physical trauma. In other cases antidepressants (eg Amitriptyline) improve IBS. However, our overwhelming experience is that patient's whose illnesses have not responded to the usual interventions are told that it is "stress" which is undermininng to the patient's judgement and intuition: we can assure you that most cases of IBS have a physical cause, with or without a stress trigger.


Eating large, infrequent meals can put significant pressure on the digestive system, and is a possible factor in indigestion and reflux. Similarly, under-eating, if severe, may lead to malnutrition, disturbance to metabolism and energy, and may be a result of, or lead to, psychological disorders. IBS is sometimes improved by correction of the diet. If lack of dietary fibre is considered to be a cause, the addition of dietary fibre should proceed for at least one week before re-assessment. Some patients achieve improvement in symptoms by following the FODMAP diet. More recently, some patients have tried the Cordas diet, with some improvements.


The following should be checked before a diagnosis of IBS is made:

  • Food sensitivity testing
  • Coeliac screening: Gliadin antibody  test or IgA antibodies to transglutaminase
  • History, lifestyle, dietary factors
  • If any ‘red flag’ symptoms, such as rectal bleeding.

On examination

Palpation may reveal a tender (spastic) colon or a loaded colon if there is constipation.  The patient may experience pain anywhere in the abdomen, including the upper right quadrant (hepatic flexure) or the upper left quadrant (splenic flexure) when there is constipation. While the pain is most often felt in the descending colon, it may be referred from any location in the abdomen.  

Causes and Categories of IBS

I have found it useful to categorise 15 types of IBS, as detailed below.  These categories may be diagnostic, for example intestinal parasites as in Category 1, or offer a particular treatment where no other seems relevant, as in Category 13 IBS. These categories are not exclusive: there is overlap found with most IBS cases, each of which may need a sequential treatment protocol.

Category 1: Intestinal Parasitosis

Evidence of Parasitic IBS

Our clinic audit shows 70 per cent of IBS cases display a sensitivity to, or have symptoms suggesting, intestinal parasites. Only a small number of these patients are able to date their symptoms from a previous episode of gastroenteritis or traveller’s diarrhoea. One study suggests that infectious gastroenteritis is associated with an 11-fold increase in the risk of developing IBS. The majority of cases, however, have no recorded (or remembered) acute episode of diarrhoea. Indeed, any colonisation of the bowel by pathogens has not necessarily had an acute onset. An asymptomatic patient with pre-existing gut dysbiosis will be predisposed to intestinal parasites because the disturbance to normal gut flora undermines the gut’s functional immunity.    

Dr Tom Borody, director of Centre for Digestive Diseases in Sydney, says many patients with IBS have the parasites dientamoeba fragilis or blastocystis hominis which, in Australia, are more common than giardia. According to Borody, laboratory detection requires a special fixative stool test which prevents degradation (as compared to fresh stool test which does not show the organism). In one study, patients in the controlled clinical trial displayed these symptoms: 

  • Irregular bowel habits
  • Bloating & cramping
  • Diarrhoea or constipation
  • Nausea, fatigue, anorexia.

Adults were given Doxycycline and Iodoquinol; and children were given Flagyl and Iodoquinol (or placebo). 67 per cent of patients receiving these drugs reported significant improvement in all symptoms. This is in accord with my own clinical findings where we use a homeopathic anti-parasitic medicine for IBS treatment. 

Reliable testing for parasites

One problem with achieving an accurate diagnosis of intestinal parasites is reliable pathology testing. As stated by Borody, above, one specialist pathology laboratory in Melbourne says that due to the lifecycle of parasites such as blastocystis hominis, the parasites may not be present in every stool. For this reason, testing over a 3-day period is necessary. Specialist laboratories recommend the use of a special fixative when collecting stool samples, without which the evidence of parasites may degrade before the sample reaches the laboratory. Stool samples should be taken over three consecutive days. Eosinophilia will be found in some cases of intestinal parasitosis and can therefore alert one to the need for a stool test.   

Dysbiosis & parasitosis

We know that a low level of the normal beneficial bacteria (gut dysbiosis) can lead to the proliferation of opportunistic pathogens, both bacteria and fungi, which are normal gut residents. These are normally kept in check by the beneficial bacteria. Dysbiosis may also facilitate infestation by intestinal parasites (ie organisms foreign to the human gut). But it is not always known what came first: did gut dysbiosis create the environment for parasitic infestation or did the parasites enter the gut and digest the beneficial bacteria? 

Some Common Intestinal Parasites

  • Ancylostoma canium (dog hookworm loves to burrow through the skin of those who walk barefoot in tropical areas)
  • Blastocystis hominis
  • Cryptosporidium parnum
  • Dientamoeba fragilis
  • Entamoeba histolytica (can be misdiagnosed as Inflammatory Bowel Disease when it causes chronic amoebic colitis)
  • Fasciolopsis buskii
  • Giardia
  • Strongyloides sterc
  • Taenia
  • Toxoplasmosis gondii
  • Trichinella


Adults or children will have one or more of the following symptoms:   

  • Abdominal pain especially umbilical
  • Allergies (including colds and flus)
  • Anaemia
  • Anorexia
  • Anxiety*
  • Bloating
  • Constipation*
  • Diarrhoea*
  • Emaciation
  • Fatigue
  • Flatulence
  • Flushes of heat
  • Insomnia
  • Irritability*
  • Nasal itch*
  • Nausea
  • Night terrors*
  • Nocturnal fever*
  • Rectal itch*
  • Restless leg syndrome
  • Skin itch or ‘crawling’
  • Teeth grinding*
  • Variable appetite*
  • Weakness
  • Weight loss

*These symptoms are commonly found in children 

Children & IBS

I have found that in almost every case, a child presenting with any of the above symptoms will have intestinal parasites. Frequently children with intestinal parasites will have irritability or nightmares. Children with ongoing diarrhoea, steatorrhoea and poor weight gain should of course be assessed for Coeliac Disease. 

Constipation & Diarrhoea

While diarrhoea is an acknowledged symptom of intestinal parasitosis, it is less well known that constipation may also be generated, or worsened by, the presence of parasites. In any event, it is clear from a perusal of the above symptoms that parasites have an effect on the nervous system, which can result in mood disorders.

Category 2: Dysbiosis Caused by SIBO and/or Candida of the GIT

Bacterial (SIBO) or yeast (Candida) overgrowth of the small intestine is very common. It found in women who have a history of vaginal candida (monilia). It is also found in patients who have had many courses of antibiotics prescribed when they were young. Patients who have a high stress life, plus the ingestion of too much sugar, can push them into both SIBO or Candida syndromes.  It is not an intestinal parasite. Intestinal parasites are foreign organisms, not comprising the normal bowel flora of humans. Candida is a normal organism found in the human gut which has proliferated because of ongoing use of antibiotics, the contraceptive pill or other cause. 

The use of antibiotics predisposes to candida overgrowth. Antibiotics destroy many of the beneficial bacteria in the gut, but do not affect candida albicans. Consequently, candida able to proliferate since it is not kept in check by normal gut flora.  

Overgrowth of opportunistic bacterial pathogens also occurs in gut dysiosis. Overgrowth of proteus, streptococcus and staphylococcus are thought to contribute to IBS symptoms. 


  • Abdominal bloating & flatulence
  • Sugar and carbohydrate craving and/or intolerance
  • Mood swings
  • History of thrush or vaginitis
  • Fatigue
  • Intestinal hyperpermeability ("leaky gut"): causing brain fog. See further below under Food Sensitivity.
There are several variants to this dysbiotic pattern described, namely that involving putrefaction of the bowel contents; another involving deficiency of essential digestive enzymes, and another, though less common, involved high levels of potentially pathogenic bacterial colonies. There can all be demonstrated by special digestive stool analysis, and have their own sets of particular symptoms. Probiotics generally help most of these categories, but are not the primary treatment.

Category 3: Emotional

As already elucidated by the medical profession, emotional stress  plays a large part in aetiologies of IBS. One study concluded that 97 per cent of those in the study experienced worsening of their symptoms when exposed to emotional stressors. Relaxation techniques or oral nervine aids may play a part in reducing symptom severity, however these do not offer a cure. Another study found that Cognitive Behavioural Therapy enhanced the treatment of IBS patients who were taking antispasmodic medication. 


  • IBS symptoms +
  • Symptoms are aggravated during times of stress
  • Symptoms may be better during sleep
  • Thinking about symptoms may worsen them.

Category 4: Food Sensitivity

Patients may have undiagnosed lifelong food sensitivities, the most common of which are:

  • Wheat and gluten
  • Cow’s milk products
  • Yeast
  • Salicylates
  • the FODMAP food lists.
In most cases, food sensitivity (not allergy) is secondary to some primary gut disturbance; for example, patients with post-parasitic IBS (Category 1) almost always have food sensitiviy, as do those with Biliary stasis (Category 7). Here are some of the other underlying factors in food sensitivity:

Leaky gut & dysbiosis

Food sensitivity is thought to arise from ‘leaky gut syndrome’. Leaky gut is an increase in the permeability of the intestinal mucosa to luminal macromolecules, antigens and toxins. This can be associated with inflammatory, degenerative and/or atrophic mucosal damage. Dysbiosis may be a predisposing factor to leaky gut, and can result from the use of:

  • Antibiotics
  • Antacids
  • Analgaesics.
 Some patients with Leaky gut have a large accumulation of elemental mercury and will require heavy metal chelation.


It is also postulated that prolonged emotional stress can predispose to both dysbiosis and leaky gut. Both may cause symptoms suggestive of food sensitivity. 

Food sensitivity can also be caused by the presence of intestinal parasites, even if there is no pre-disposing dysbiosis. When the parasites are removed the food sensitivity improves. 

Gut inflammation->constipation & diarrhoea->stress cycle

The regular consumption of foods to which one is sensitive may cause chronic gut inflammation. Serotonin and acetylcholine, which play a significant part in gastrointestinal motility, may be affected by the chronic inflammation. This may lead to either constipation or diarrhoea, which could therefore be seen as a neurological problem. If it were not so, then emotional stress could play no part in the manifestation of these symptoms. Anyone who has experienced diarrhoea before public speaking knows that there is a clear relationship! It is possible for gastrointestinal disorders to both cause, and be caused by, emotional stress. Consequent chronic mood disorders are also a possible result of gastrointestinal dysfunction. Our vernacular represents this understanding when we use expressions such as ‘I have a gut feeling that…..’. 

Other common causes of what appears to be food sensitivity symptoms are gallbladder stasis and hypochlorhydria. 


  • In addition to other symptoms, there is aggravation of symptoms following a certain food or food group
  • In leaky gut, symptoms may also be emotional and behavioural (eg, think of how child behaviour is influenced by food colourings).

Category 5: ‘Never Well Since’

The onset of the IBS may date from a specific previous illness event, such as surgery, allopathic medication, or another event, for example:

  • Abdominal surgery
  • Antibiotic use
  • Glandular fever (Infectious Mononucleosis)
  • Oral Contraceptive Pill (OCP): use of the Pill gives rise to a special category of IBS which we have identified in young women called 'Xenoestrogenic IBS' and requires a special treatment plan.
  • Other bacterial or viral diseases


  • There are no symptoms specific to this category. Diagnosis is made solely from the patient’s history, noting a cascade of symptoms since a specific event.

Category 6 : Hypochlorhydria & Gastro-oesophageal Reflux

A significant proportion of IBS patients also experience gastric reflux as part of their symptom picture. Reflux may be caused by hypochlorhydria (insufficient stomach acid). Reflux may also arise from inadequate bile. Excreted via the gallbladder, bile is necessary to emulsify and digest oils and fats. Insufficient bile results in burning in the epigastric region: this is know as bile reflux. These are all variants of Gastro-oesophageal reflux (GORD - or GERD in USA).


  • IBS symptoms as described +
  • Heartburn (sharp or burning pain) felt at the cardiac orifice, oesophagus, trachea or larynx
  • Dysphagia
  • Voice loss or croaky voice
  • Regurgitation and/or excessive burping
  • Sensation of tightness around the throat
  • Abdominal bloating
  • Belching and full sensation after eating if there is hypochlorhydria.

Category 7: Biliary Stasis - see also above under Category 6

Sludge of the bile duct is a not uncommon cause of the symptoms below, as is gallbladder calculi. Unlike calculi, sludge is not evident on ultrasound, and can be best diagnosed on the presenting symptoms. That means, even if you have had your gallbladder 'checked out' that does not exclude this category of IBS which is very common in young women. This type of IBS is relatively straight forward to treat.


  • Pale stools
  • Nausea
  • Afternoon headaches
  • Fatty food intolerance
  • Dull epigastric pain
  • Dull pain in right hypochondrium.

Category 8: Gastritis & Peptic Ulcer

Some IBS patients also experience gastric symptoms as part of their IBS symptom picture. If reflux and/or hypochlorhydria are chronic, gastritis and ulceration can result. While the symptoms are similar to Category 6, with gastritis and ulcer the disease has progressed into a pathology. 


  • IBS symptoms as described +:
  • Heartburn (sharp or burning pain) felt at cardiac orifice, epigastrium, oesophagus, trachea or larynx
  • Dysphagia
  • Voice loss or croaky voice
  • Cough and/or mucus in the larynx, sometimes rising to the posterior nares
  • Regurgitation and/or excessive burping with or without pain
  • Sensation of tightness or lump in the throat
  • Bloating.

Category 9: Post Viral

We have identified a small group of cases whose IBS symptoms appear to be post-viral. The patient has developed symptoms since Glandular Fever, or some other viral infection.

This category is a significant cause of IBS which does not appear to have been recognised in allopathic medicine.

Patients in this category demonstrate IBS symptoms which have an acute, cyclical onset. Their symptoms may appear, for example, once per month, and last for many days to one or two weeks. They are largely free of bowel symptoms between attacks, yet they complain of  generally feeling unwell, having excessive fatigue, or vague nausea. The acute attacks often consist of severe abdominal cramps and diarrhoea. These cases can easily be confused with intestinal parasitosis. Antiparasitic medicines given to these patients will afford no relief, and may worsen the case. 


  • IBS symptoms as described +:
  • Fatigue
  • Nausea
  • Repeated colds, flus or throat infections (a sign of lowered immunity)
  • Clear onset of symptoms with or soon after a viral infection.
  • Ongoing cyclic diarrhoea or abdominal cramps
  • Migraine
  • Unexplained myalgia.

Category 10: Constipation

Misuse of laxatives and lack of dietary bulk (fibre) may cause a ‘lazy’ bowel, with inadequate peristalsis and muscle spasm. Constipation may also be a result of intestinal parasitosis and gut dysbiosis. I suspect that emotional stress is a factor more often than is commonly recognised. Many patients with constipation relate how they have a history of ‘holding on’ until they arrived home to go to the toilet.  


  • Less than one bowel motion per day
  • Overflow symptoms, with small amounts of stool being passed, which may be loose
  • No urge for stool
  • Ineffectual urging for stool.

Causes of Constipation

Not all constipation is IBS related, particularly if caused by one of the factors below. 


  • Inadequate fluid intake
  • Insufficient exercise
  • Problems relating to toileting, ie too busy to go to the toilet particularly first thing in the morning
  • Poor diet, lacking in fruit, vegetables and fibre.

Central Nervous System Disorders

  • CVA
  • Brain tumours
  • Parkinson’s disease
  • Depression
  • Dementia
  • Multiple sclerosis
  • Spinal cord lesions
  • Cauda equine lesions
  • Shy-Drager Syndrome

Allopathic Drugs

  • Analgesics particularly those containing codeine
  • Opiates
  • Antacids
  • Antispasmodics
  • Antidepressants
  • Antipsychotics
  • Anti-parkinsonian medications
  • Anti-diarrhoeal agents
  • Anticonvulsants
  • Anti-inflammatory agents
  • Mineral overdoses

Metabolic or Endocrine Disturbances

  • Hypothyroidism
  • Diabetes
  • Hypercalcaemia
  • Hypokalaemia
  • Porphyria


  • Pregnancy
  • Immobility (bed rest etc).

Category 11: Diarrhoea & Faecal Incontinence

Inappropriate diet or food sensitivity may predispose to diarrhoea. Too much dietary fibre in some constitutions may be one reason. Diarrhoea from dietary fibre can indicate gut dysbiosis. Diarrhoea is often caused by intestinal parasites, as already described. 

Non-IBS Diarrhoea

Causes of faecal incontinence and diarrhoea which are not related to IBS are:

  • Congenital
  • Obstetric
  • Constipation overflow (faecal impaction appears as diarrhoea)
  • Neurological disease
  • Rectal prolapse
  • Iatrogenic trauma to anal sphincter
  • Post-colon and rectal surgery
  • Spinal trauma
  • Idiopathic.


  • Unformed or partially formed, urgent stool.

Category 12: Diet & Lifestyle

Some ‘IBS’ can be corrected simply with dietary and lifestyle adjustments. Skipping meals and reliance on convenience foods will result in inadequate nutrition and disturbance to bowel habits. Taking vitamins may assist with nutritional deficiencies, but regular meals which include fresh fruit and vegetables plus plenty of fluids are essential for normal bowel function.  

Therefore, inappropriate lifestyle habits must also be considered, for example,   the use of regular recreational drugs. An inappropriate working environment may lead to disease. For example, a person prone to insomnia should not work night shifts, but requires a regulated sleeping routine. 

Lifestyle factors may include: 

  • Excessive use of caffeine
  • Inadequate water intake
  • Inadequate sleep
  • Long working hours
  • Poor nutrition
  • Lack of exercise
  • Eating meals too quickly (thus swallowing air)
  • Not following one’s urge to go to the toilet – ie too busy
  • Too much sugar and starch is conducive to SIBO and Yeast overgrowth: see Category 2 above.

The eating of large infrequent meals may put significant pressure on the digestive system, and is a possible factor in indigestion and reflux. Similarly, under-eating, if severe, may lead to malnutrition, disturbed metabolism and energy, and may be a result of, or lead to, psychological disorders.