Dental caries and periodontal disease are wide-spread oral illnesses whose etiology is intimately associated with the consumption of carbohydrate sweeteners. Since dental caries is multifactorial in nature, it is reasonable to assume that there is no single method, usable in the foreseeable future, which would lead to its eradication. Consequently, any new caries preventive measures must function coherently with those currently in use, so that the concerted action of all methods would lead to the best cariostatic effect. Strict restriction of sucrose intake without suggestion of alternatives is not realistic. This fact has given rise to attempts to replace sucrose, especially in products consumed between meals, with sweeteners that are less cariogenic. Human clinical trials and several animal experiments have shown promising clinical results obtained by replacing sucrose with certain sugar alcohols (polyols). Among the sugar alcohols, the best results so far have been obtained with xylitol, which is chemically a pentitol containing five carbon atoms. Chewing gums containing xylitol have been shown to be strong instruments against caries in caries-active age-groups and in high-risk subjects. More research is needed to assess the ability of mixtures of xylitol with sorbitol, palatinit, maltitol, other sugar alcohols, and intense sweeteners to prevent oral plaque diseases. Although thorough clinical trials on the relationship between carbohydrate sweeteners and periodontal diseases have not been performed, the available data indicate that dietary polyols may have a restricted dampening effect on periodontal and gingival inflammations.