Polysaccharides form a diverse and complex family of biological macromolecules. They are polymeric carbohydrate molecules composed of long chains of monosaccharide units joined together by glycosidic linkages and on hydrolysis give the constituent monosaccharides or oligosaccharides. Polysaccharides occurring in nature often have high molecular weights. A large number of polysaccharides contain between 100 and several thousand monosaccharides. They are usually polydispersed in nature and may contain a wide range of closely related structures.