Stannous fluoride was frequently used as a vehicle for fluoride in preparations used in caries prophylaxis in the 1960s and 1970s. At present it is not much used, although extensive research during the last two decades has established that stannous fluoride possesses several interesting properties which demonstrate that it deserves to be used in the prophylaxis against both gingivitis and caries. In the following, a review of the clinical properties of stannous fluoride is presented, together with a discussion of its merits compared with other fluoride vehicles in current use.