To evaluate the long-term outcome of a mother-child project in which mothers (n=173) with high counts of salivary mutans streptococci were randomly assigned to daily chewing gums containing xylitol (A), chlorhexidine/ xylitol/sorbitol (B), or sodium fluoride/xylitol/sorbitol (C) for one year, when the child was between 6 and 18 months. 140 of the off-springs were re-examined at the age of 10 years and 204 children of mothers with low counts of salivary mutans streptococci three months after delivery served as positive controls (D). Caries was scored in the young permanent dentition on enamel (noncavitated) and dentine (cavitated) levels. The long-term attrition rate was 15%. The overall caries prevalence in the combined groups at 10 years of age was 31% (21% non-cavitated; 17% cavitated) with a mean DS of 0.7 (SD 1.3). No significant differences were found between the three experimental groups (A-C), or when compared with the control group. A statistically significant (p<0.05) positive relationship between the levels of salivary mutans streptococci at 18 months of age and the caries experience at the age of 10 years was disclosed for all groups combined. No beneficial longterm effects of maternal xylitol gum exposure on their children's dental health were demonstrated when compared with gums containing chlorhexidine and fluoride.