The present invention provides a carbonated beverage capable of suppressing the elevation of blood sugar level by intestinal flora without requiring a. Beta. - glucan component.A method for inhibiting the increase in blood glucose level by an intestinal flora using a carbonated drink which is a dissolved water containing citric acid and sodium bicarbonate as a bicarbonate as an organic acidThe dissolved water is contained in the ratio of 2 to 7 of sodium bicarbonate to citric acidA method of inhibiting a rise in blood glucose level by an intestinal flora characterized by the fact that the amount of carbon dioxide gas is pressed into the dissolved water by an amount of 1000 to 10000 ppm, and a carbonated beverage which is capable of suppressing the increase in blood glucose level.Diagram