Xylitol is the first rare sugar that has global markets. It has beneficial health properties and represents an alternative to current conventional sweeteners. Industrially, xylitol is produced by chemical hydrogenation of D-xylose into xylitol. The biotechnological method of producing xylitol by metabolically engineered yeasts, Saccharomyces cerevisiae or Candida, has been studied as an alternative to the chemical method. Due to the industrial scale of production, xylitol serves as an inexpensive starting material for the production of other rare sugars. The second part of this mini-review on xylitol will look more closely at the biotechnological production and future applications of the rare sugar, xylitol. (Nigam and Singh 1995). Currently, the annual production lies between 20,000 and 40,000 t per year with a market value of 40-80 euroM. These are estimated figures, as exact numbers are not publicly available. The use of metabolically engineered yeasts, Saccharomyces cerevisiae or Candida, has been studied as an alternative for industrial production of xylitol. However, the biotechnological method has not yet been able to overcome the advantages of chemical dehydrogenation.