In recent times it has come to be realized that pentoses are important as building blocks in the organism and as intermediate products in metabolism. The finding that ribose and desoxyribose are nucleic acid con­ stituents and the discovery of the pentose-phosphate cycle have put these substances in a central position in biochemical research. The con­ current realization that the pentitol, xylitol, is involved in an important metabolic cycle and that the body can handle it in quantities comparable in magnitude to the well-known carbohydrates has resulted in extensive experimental and clinical studies, especially in Germany and Japan. Some of the properties of xylitol, e.g. its independence of insulin and also its utilization in other disturbances of the glucose metabolism have aroused considerable interest among clinicians. The initial experiments have shown that xylitol may be of significant therapeutic value, and more extensive research work into the possible clinical applications of xylitol is being undertaken. Xylitol research is a typical example of the interrelation of the clinical and experimental approaches to a problem. These rapid advances in knowledge made it necessary to bring together workers in both the research and clinical fields in order that they might discuss their findings in critical fashion and advance our understanding of this subject.