Various components in green and black tea, the beverages made by infusing appropriately processed dried leaves of Camellia sinensis , notably simple catechins, have properties in vitro that suggest an anti-cariogenic activity. These include: a direct bactericidal effect against Streptococcus mutans and S. sobrinus ; prevention of bacterial adherence to teeth; inhibition of glucosyl transferase, thus limiting the biosynthesis of sticky glucan; inhibition of human and bacterial amylases. Studies in animal models show that these in-vitro effects can translate into caries prevention. A limited number of clinical trials in man suggest that regular tea drinking may reduce the incidence and severity of caries. If substantiated, this could offer a very economical public health intervention.