What Causes Flatulence?

Flatulence can have various causes, ranging in severity from 'minor' to 'generally fatal'.  Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.

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Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms.  In order to diagnose flatulence, we could:

  • Research the topic
  • Find a doctor with the time
  • Use a diagnostic computer system.
The process is the same, whichever method is used.

Step 1: List all Possible Causes

We begin by identifying the disease conditions which have "flatulence" as a symptom.  Here are eight of many possibilities (more below):
  • Irritable Bowel Syndrome
  • Giardia
  • Poor Digestion
  • Stomach Acid Deficiency
  • Lactose Intolerance
  • Crohn's Disease
  • Blastocystosis
  • Diverticular Disease

Step 2: Build a Symptom Checklist

We then identify all possible symptoms and risk factors of each possible cause, and check the ones that apply:
trace amounts of occult blood
weak appetite
slight abdominal distension
African ethnicity
upper abdomen pain after night meal
frequent unexplained nausea
very foul-smelling flatulence
occasional mucus in stools
mild left iliac discomfort
meals worsen epigastric pain
regular unexplained nausea
Crohn's disease in remission
... and more than 70 others

Step 3: Rule Out or Confirm each Possible Cause

A differential diagnosis of your symptoms and risk factors finds the likely cause of flatulence:
Cause Probability Status
Giardia 92% Confirm
Lactose Intolerance 30% Unlikely
Crohn's Disease 21% Unlikely
Poor Digestion 5% Ruled out
Stomach Acid Deficiency 4% Ruled out
Diverticular Disease 4% Ruled out
Irritable Bowel Syndrome 2% Ruled out
Blastocystosis 0% Ruled out
* This is a simple example to illustrate the process

Arriving at a Correct Diagnosis

The Analyst™ is our online diagnosis tool that learns all about you through a straightforward process of multi-level questioning, providing diagnosis at the end.

In the Gastrointestinal Symptoms section of the questionnaire, The Analyst™ will ask the following question about flatulence:
Do you suffer from excess lower bowel gas (flatulence)? The average adult passes gas ("farts") 8 to 20 times a day, but this depends on various factors. Try to compare yourself to others with similar diet and eating habits.
Possible responses:
→ No / average / only after overeating / don't know
→ Yes, but it is probably due to my diet
→ Somewhat more than most people
→ Very much more than most people
Based on your response to this question, which may indicate flatulence, excessive flatulence or severe flatulence, The Analyst™ will consider possibilities such as:
Gallbladder Disease

Persistent and severe flatulence may be a symptom of gallbladder problems.

IBS (Irritable Bowel Syndrome)

The altered digestion found in IBS will usually lead to higher gas production.  If intestinal transit is too quick, food is only partially digested.  Natural bacteria residing in the gut will cause fermentation of this food, producing gas.  Fast-moving bowel contents may also lead to pockets of trapped gas, worsening the problem.  Some studies suggest that the populations of gut bacteria in IBS patients differ from the normal, with more 'bad' than 'good' bacteria, which can cause excess flatulence.

Lactose Intolerance

"Lactose malabsorption and lactase deficiency are chronic organic pathologic conditions characterized by abdominal pain and distention, flatulence, and the passage of loose, watery stools.  Once correct diagnosis is established, introduction of a lactose-free dietary regime relieves symptoms in most patients... who remain largely unaware of the relationship between food intake and symptoms." [Journal of Clinical Gastroenterology, 1999 Apr, 28:3]


Gas can be caused by stress and the nervous habit of frequent swallowing.

Concerned or curious about your health?  Try The Analyst™
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