A sugar alcohol (also known as a polyol, polyhyric alcohol, or polyalcohol) is a hydrogenated form of carbohydrate, whose carbonyl group (aldehyde or ketone, reducing sugar) has been reduced to a primary or secondary hydroxyl group. Its general formula is H(HCHO)n+1H, whereas sugar's is H(HCHO)nHCO. They are commonly used for replacing sucrose in foodstuffs, often in combination with high intensity artificial sweeteners to counter the low sweetness. Furthermore, they do not contribute to tooth decay.