A total of 91 schoolchildren, 13 years of age, were distributed into three groups. Three test dentifrices were used containing 0.1% NaF, 0.1% NaF and 2% chlorhexidine, and 2% chlorhexidine, respectively. The caries increment and gingival conditions over a period of 2 years were recorded. The caries data of the groups were compared and related to two reference groups in order to estimate a possible influence upon the study results by a change in caries incidence general to the area and age groups in question. There was less caries in the group using the dentifrice containing fluoride and chlorhexidine than in the two other test groups. The differences in caries increment between the groups were not statistically significant. The gingival health seemed to improve in all groups, but there were no statistically significant differences between the groups. The caries data from the reference groups indicated that the general trend towards reduced caries incidence was different from that of the study group.