Human flatulence in public

Excessive wind
Intestinal bloating
Excessive intestinal gas
Accumulation of gases in the stomach or bowels as a result of indigestion or swallowing air when eating, especially when eating rapidly. It is also caused by the fermentation of certain foods, particularly beans, carbonated beverages, vegetables, fruits, and grains. Air in the stomach may be expelled from time to time through the mouth as a belch, whereas that in the bowels may be expelled through the anus.
The healthy human digestive system works with 7-10 litres of gas per day, all of which has either been swallowed or produced by fermentation. Only a fraction of that gas is expelled; most people fart between 300ml and 2 litres of gas a day, the average being half a litre. The average person releases gas ten to twenty times per day; the normal average is 13.4 farts a day.

Abnormal and unusually disagreeable flatulence may be the result of imbalanced dietary intake, irritable bowel syndrome, diverticulitis, malabsorption or even pancreatic disease.

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In certain cultures belching after a meal may be considered a polite indication of satisfaction with the meal.
(E) Emanations of other problems