The belief that sugar exerts a harmful effect on teeth has been taught by the dental profession and accepted by the public for many years, even though biochemically very little is known about the various types of sugars in solution in the oral secretion. The inadequacy of the information available on this question of inestimable importance prompted an investigation to determine: first, whether glucose2 is a normal constituent of human saliva and, if so, in what quantities it is present; second, whether glucose is present in the saliva-possibly in increased or decreased amounts-under pathological conditions such as diabetes, glycosuria and uremic nephritis; and third, whether the ingestion of sugars would temporarily raise the salivary sugar content.3Since a large number of experiments have been conducted on animals, a historic survey is given below. LITERATURE