The cariostatic efficacy of rinsing with a 0.05–0.2% neutral sodium fluoride solution has been clearly demonstrated, especially in supervised school-based programmes in moderate and high caries risk children. The cost-benefit effect, however, is questionable in populations with low caries prevalence, and fluoride rinsing programmes are gradually being replaced by more individual fluoride therapy comprising combinations of fluoride toothpastes, tablets, or varnishes. Fluoride varnishes were developed as individual alternatives to conventional topical fluoride application and are today gaining acceptance for clinical application. Two varnishes, Duraphat® containing 5%wt NaF and Fluor Protector® with 0.9% wt fluor silane, are available commercially. The clinical effects seem to depend mainly on application frequency, especially in high caries risk groups. The cost-benefit effect is high, but can be increased by delegating application to auxiliary personnel in conjunction with regular dental visits. Toxicologically both fluoride mouthrinses and fluoride varnishes are safe if used as directed.