Gas production in the large intestine: As a factor of gas evolution in the large intestine, fermentation by intestinal microbial flora of carbohydrates not absorbed in the small intestine is important. Hydrogen, carbon dioxide gas and methane gas are generated by fermentation. Such a mechanism is gas evolution due to the promotion of small  intestinal transit, and it can be used for people with digestive absorption disorder, intake of milk (lactose) in lactase deficiency, various vegetable foods (in particular, indigestible oligosaccharides and polysaccharides Pulp, including many), and also caused by ingestion of lactulose. The occurrence of gas symptoms in IBS is not only an increase in intestinal gas, but also an obstacle to passage of gas in the intestines due to convulsion of the large intestine and an increase in susceptibility to dilation of the large intestine and an increase in internal pressure are important, even the same amount of gas as normal can cause symptoms in IBS. The occurrence of gas symptoms in IBS is not only an increase in intestinal gas, but also an obstacle to passage of gas in the intestines due to convulsion of the large intestine and an increase in susceptibility to dilation of the large intestine and an increase in internal pressure are important, even the same amount of gas as normal can cause symptoms in IBS.Treatment of gas symptoms should avoid fermentable foods such as beans. Also, lactose intolerant people should avoid milk.

(In Nihon-Rinsho, 1994)