New research published show that coffee extract has antibacterial activities against certain microorganisms.3. and 6. These include Gram-positive and Gram-negative bacteria, including Streptococcus mutans, which are a major cause of dental caries. 6 According to Namboodiripad and Kori,6 subjects who consumed coffee daily without sugar and milk showed decayed missing and filled surface (DMFS, index used for measuring caries experience in dental epidemiology) scores of 2.9, whereas in subjects who did not consume coffee, the DMFS score was 4.0, demonstrating the anti-caries properties of coffee. The anti-caries effect of the substance has been related to: