New Study Looks at Cannabinoids and Oral Bacteria

Researchers from Henan University (China) recently reported that Cannabidiol (CBD) and Cannabigerol (CBG) reduce biofilm development by mixed species of bacteria and yeast on enamel surfaces. The study was published in the International Dental Journal on September 19, 2026.

The team, led by Yuankun Zhai, worked with two microbes that often live together in the mouth: the bacterium Streptococcus mutans and the yeast Candida albicans. To copy conditions on real teeth, the scientists grew some of these colonies on saliva-coated hydroxyapatite discs. Hydroxyapatite is the mineral that makes up most of tooth enamel.

At a dose of 5 micrograms per milliliter, both cannabinoids reduced living S. mutans cells by more than 2 logs, which is a drop of over 99%. The yeast’s survival also fell sharply. The biofilms also grew much more slowly. Metabolic activity dropped by 96% and total biomass by 80% compared with untreated samples.

The researchers then applied the compounds again over several days. With repeated CBD exposure, S. mutans counts were 92% lower after two days and 95% lower after three. CBG was close behind, with reductions of 90% and 92%.

The authors added the compounds directly to lab cultures. No consumer CBD products were tested. The authors believe this is the first study to test CBD and CBG on this specific two-species community.

The authors point out that the work had limits. Lab discs can’t recreate everything that happens in a real mouth, such as changing diets, the full mix of plaque organisms, and the body’s own defenses. Zhai and colleagues wrote that the results “provide a basis for future studies using more complex oral biofilm systems.”

CBD and CBG are non-intoxicating compounds from the cannabis plant. Earlier lab work showed that cannabinoids act against oral bacteria when tested against each species separately. Mixed communities are harder to break up, so the Henan team chose a bacteria-yeast pairing that more closely resembles what forms on teeth. In 2020, a small study in Cureus tested cannabinoids on plaque samples from volunteers. It found they lowered bacterial counts about as well as common oral care products.