Mannitol is a white, crystalline organic compound

Organic compound

An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

 with the formula (C₆H₈(OH)₆). This polyol

Polyol

A polyol is an alcohol containing multiple hydroxyl groups. In two technological disciplines the term "polyol" has a special meaning: food science and polymer chemistry.- Polyols in food science :...

 is used as an osmotic diuretic

Osmotic diuretic

An osmotic diuretic is a type of diuretic that inhibits reabsorption of water and sodium. They are pharmacologically inert substances that are given intravenously. They increase the osmolarity of blood and renal filtrate...

 agent and a weak renal

Kidney

The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

 vasodilator. It was originally isolated from the secretions of the flowering ash, called manna

Manna

Manna or Manna wa Salwa , sometimes or archaically spelled mana, is the name of an edible substance that God provided for the Israelites during their travels in the desert according to the Bible.It was said to be sweet to the taste, like honey....

 after their resemblance to the Biblical food, and is also referred to as mannite and manna sugar.
In plants, it is used to induce osmotic stress.
Mannitol is a sugar alcohol

Sugar alcohol

A sugar alcohol is a hydrogenated form of carbohydrate, whose carbonyl group has been reduced to a primary or secondary hydroxyl group . Sugar alcohols have the general formula Hn+1H, whereas sugars have HnHCO...

; that is, it is derived from a sugar by reduction, with a molecular weight of 182.17 g/mol, and a density

Density

The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

 of 1.52 g/mL.