Glucose, Or Grape Sugar, is present in almost all fruits, in some in abundant quantities. In peaches, pineapples, and strawberries it is found with cane sugar, and in grapes and cherries it is combined with other varieties. Grape sugar is known by the name of dextrose. When grapes are dried to form raisins, the little dried masses on the outside are dextrose. Commercial glucose is usually obtained by boiling starch with acid, and it is sold in a syrupy form. When heated it turns brown and is used as sugar-colouring. Glucose mixed with egg albumin is largely employed by confectioners in the preparation of icing and fondants.

Levulose, or fruit sugar, is found in most fruits; it is difficult to crystallise. It is now sold under the name of "Diabetin," for the use of diabetics, on the ground that it is better borne than any other form of sugar. Diabctin is sweeter than cane sugar, and has a somewhat fruity taste. It may be taken in considerable quantities without disordering digestion, as saccharin is apt to do.