Experts believe that the major cause of abnormal bloating is excessive eating, and sleeping swallowing or what is known as aerophagia. Other causes of bloating are irritable bowel syndrome, diabetes, functional dyspepsia or transient constipation. In rare cases, bloating may occur in individuals who have milk intolerance (lactose intolerance), parasite infections like giardia, food poisoning (bacteria), coeliac disease, severe peptic ulcer disease, bowel obstruction or after certain types of abdominal surgery. Heart failure and cirrhosis are also a common cause of distension. In both of these disorders, fluid accumulates in the abdomen and creates a sensation of fullness. Women are more prone to bloating and often complain about these symptoms during menstruation. It is believed that individuals who develop distension either have poor motility of their intestines or are hypersensitive to gut sensations. Experts believe that in most cases, the combination of swallowed air and fluid in the abdomen creates a swirling sensation in the bowels that leads to bloating. Moreover, when the intestines are swollen with air, they push up against the diaphragm and can induce a sensation of pressure in the lower chest. Studies have shown that swallowing air during eating or delayed emptying of the stomach from hyperacidity leads to bloating after a meal. Individuals who are constipated also complain of bloating. In some individuals who are hypersensitive, any volume of air may be perceived as fullness and there may not be actual abdominal distension. In some individuals with abdominal bloating, there may be an increasing abdominal girth either from fluid or air accumulation.

Abdominal distension (or "distended abdomen") can be a sign of many other conditions, including:

Patients should understand that bloating is not life threatening and there is no need to rush to a physician every time an episode occurs. In most cases, bloating can be handled with simple home remedies and changes in life style. However, when bloating has been persistent or recurrent. It is wise to see a physician to ensure that there is no organic cause for the problem. Physicians usually check stools for parasites and other infections.

Certain foods have been known to worsen bloating. Poorly digested components of many foods are excreted into the large intestine where they are degraded by bacteria, producing excess gas. Depending on the undigested component, this may affect the odor and the volume of gas created.[citation needed] Excess dietary fiber intake is a known cause of belching, gas and bloating. More than 20-25 grs of dietary fiber per day is not recommended.

Many vegetables are known to cause bloating due to high levels of fiber and undigestible sugars such as raffinose (e.g. beans, cabbage, broccoli) .

There are many individuals who are unable to tolerate dairy products because of lactose intolerance. Such foods should be eliminated from diet if symptoms develop.

For some people, recurrent distension symptoms worsen their quality of life and thus many resort to health supplements or medications. BeanoTM is a formula containing enzymes that help break down complex carbohydrates and vegetables. This formula can help reduce gas and belching but often does not reduce bloating. Other over the counter formulas recommended for bloating include simethicone and activated charcoal. These are widely used to treat excessive gas and bloating but their efficacy is questionable. Probiotics are also used to treat bloating but not everyone responds to these health supplements. Antidepressants in low doses have been found to help a few individuals. These agents alter gut perception of fullness and do help relieve anxiety and apprehension. Alternative health treatments which have been used to treat bloating include acupuncture and hypnosis.

gas: Flatulence · Abdominal distension · Bloating · Belching · Tympanites

stool: Fecal incontinence (Encopresis) · Rectal tenesmus

blood: Fecal occult blood