From a theoretical point of view, caries can be prevented by perfect oral hygiene and sugar abstinence. However, practice has shown that this approach is successful in individual cases only. For the whole population, effective caries prevention is still not realistic without the use of fluoride in various forms. The use of different fluoride preparations increases its efficacy. On the other hand, correct dosage is important to prevent the risk of dental fluorosis. Most of the European scientific dental associations no longer recommend the use of fluoride supplements, such as fluoride tablets or drops, as a standard procedure in caries prevention. This is due to the increasing evidence that the effect of fluoride is mainly the result of chemical reactions on the tooth surface. Therefore, fluoridated toothpastes, gels, varnishes, and rinses are more in focus. Besides this, fluoridated water and fluoridated salt are still important. Although they have a systemic effect, the efficacy of these fluoride applications results from local processes. Keywords: Fluoride, Caries