The findings of a study published in General Dentistry revealed that green tea infusion utilized as a mouthwash exhibits a good antibacterial effect on saliva and bacterial plaque. Jazmin Servin et al. aimed to determine the antibacterial effect of green tea mouthwash in 28 students (18-40 years of age).

Participants were divided into two groups: green tea (intervention, n=14) or distilled water (placebo, n=14). Preparation of  a 13% green tea infusion with 13 g of green tea was done in 100 ml of saline solution at 90°C, followed by pouring of liquid into sterile glass containers.

In this double-blind, randomized controlled study, evaluation of antibacterial activity was done by estimating the colony-forming units in the cultures of saliva and plaque samples that were procured prior to and promptly after the recruited subjects rinsed their mouth once with 10 ml of green tea or control solution.

Using t-tests, the differences prior to and after the intervention and between the two groups were analyzed. Significant inter-group differences were reported, with subjects in the green tea group showing a higher decline in the numbers of colony-forming units. Thus, infusion of green tea in mouthwash aids to control bacterial plaque.