Where does the gas come from?
The gas comes from two sources: exogenous or swallowed and endogenous gas, produced by colonic bacteria. But Analysis has shown that 90 % of intestinal gas is exogenous and only 10% is actually formed inside the intestines. What is the normal amount of gas in the intestine? Body plethysmography and argon washout techniques have shown that the volume of gas in the intestinal tract is approximately 200 ml in the fasting and postprandial states. This is so, even, in individuals who complain of excessive gas. What is the composition of intestinal gas? Nitrogen (N2), oxygen (O2), carbon dioxide (CO2), hydrogen (H2) and methane (CH4) account for more than 99% of the expelled gas. Analysis has shown that nitrogen is the predominant constituent of intestinal gas. None of the principal constituents have odour. Foul odour is mainly due to sulphur containing compounds like hydrogen sulphide, dimethyl sulphide etc. Some amount of swallowed air also passes down from the stomach into the intestines
