Probiotics are defined as live microorganisms which, when administered in appropriate amounts, confer a health benefit to the host. Although these organisms are naturally present in food and water, they can also be deliberately added to some foods because of their beneficial effects for human health. The potential application of probiotics for oral health has recently attracted the attention of several teams of researchers. However, only a few clinical studies have been conducted so far, and the results to date suggest that probiotics could be useful in preventing and treating oral infections, including dental caries, periodontal disease and halitosis. This article summarises the currently available data on the potential benefits of probiotics for oral health.