Flatus
Key points
- Flatus (flatulence) is air or gas in the intestine that is released through the rectum.
- When bacteria begin to break down undigested food in the large intestine or colon, gas is formed.
- If flatus is one of several symptoms, your doctor might need to consider the possibility of illnesses such as inflammatory bowel disease.
- This gas consists mainly of the odourless gas carbon dioxide.
Alternative names
Aerophagia, excessive gas, flatulence or "farts".
What is flatus?
Flatus (flatulence) is air or gas in the intestine that is released through the rectum. This gas consists mainly of the odourless gas carbon dioxide. Small amounts of other gases are present, such as methane and hydrogen sulphide. The unpleasant smell of intestinal gas is a result of the hydrogen sulphide or other compounds. These other compounds are mostly amines, which are produced when proteins are broken down in the colon. The amines can be particularly offensive.
What causes flatus?
When bacteria begin to break down undigested food in the large intestine or colon, gas is formed. This causes the intestine to distend (swell), which can cause cramping pain. If the intestinal wall is inflamed, it can become more sensitive than usual to normal amounts of flatus.
Even though it can cause discomfort, excessive gas is usually not a serious symptom.
There are many causes of flatus and they may vary depending on your age, gender, and associated complaints. Some of the more common causes include:
- Eating non-digestibl
- Eating foods that your body cannot tolerate (as in lactose intolerance which occurs when you lack the enzyme which digests lactose or milk sugar).
- Eating beans. There are carbohydrates in beans that cannot be digested by our enzymes so the bacteria in the colon have to break it down. The result is colonic gas.
- Acute pancreatitis.
- Irritable bowel syndrome.
- Malabsorption (which occurs when your intestine is not able to absorb nutrients) often accompanied by diarrhoea.
- Use of antibiotics.
Who gets flatus?
Anyone can get flatus. Fibre is the main cause of flatus and since fibre is necessary in a healthy diet, flatus can be seen as a sign of good health! It has been estimated the average healthy young male passes excess gas thirteen times a day.
How is flatus diagnosed?
If flatus is one of several symptoms, your doctor might need to consider the possibility of illnesses such as inflammatory bowel disease. In this case, your doctor will probably ask questions about your medical history, such as what your eating habits are like and whether you experience any other symptoms, such as diarrhoea, abdominal pain or bloating.
Frequently asked questions
What is flatus?
Flatus (flatulence) is air or gas in the intestine that is released through the rectum. This gas consists mainly of the odourless gas carbon dioxide. Small amounts of other gases are present, such as methane and hydrogen sulphide. The unpleasant smell of intestinal gas is a result of the hydrogen sulphide or other compounds. These other compounds are mostly amines, which are produced when proteins are broken down in the colon. The amines can be particularly offensive.
What causes flatus?
When bacteria begin to break down undigested food in the large intestine or colon, gas is formed. This causes the intestine to distend (swell), which can cause cramping pain. If the intestinal wall is inflamed, it can become more sensitive than usual to normal amounts of flatus. Even though it can cause discomfort, excessive gas is usually not a serious symptom. There are many causes of flatus and they may vary depending on your age, gender, and associated complaints. Some of the more common causes include:
- Eating non-digestibl
- Eating foods that your body cannot tolerate (as in lactose intolerance which occurs when you lack the enzyme which digests lactose or milk sugar).
How is flatus diagnosed?
If flatus is one of several symptoms, your doctor might need to consider the possibility of illnesses such as inflammatory bowel disease. In this case, your doctor will probably ask questions about your medical history, such as what your eating habits are like and whether you experience any other symptoms, such as diarrhoea, abdominal pain or bloating. Diagnostic tests that may be performed to rule out serious problems include:
Written and revised by
David Cohen, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.