Abstract: The invention relates to a process for preparing a noncrystallizable polyol syrup stable to heat and to alkaline medium, using a step of hydrogenation of a sugar syrup and a step of caramelization of the hydrogenated sugar syrup, wherein the hydrogenated and caramelized sugar syrup is subjected to purification on ion-exchange resins, the said purification comprising at least one passage over a strong cationic resin at a temperature of less than 50° C., the said temperature being chosen according to the level of reducing sugars desired in the noncrystallizable polyol syrup. It also relates to the use of the polyol syrup obtained for the preparation of toothpastes.