Camellia sinensis, the plant from which green and black tea are derived, has scientific evidence supporting its use in the management of gingivitis. The primary mechanism attributed to its efficacy is the presence of polyphenolic compounds, particularly catechins like epigallocatechin gallate (EGCG), which exhibit anti-inflammatory, antibacterial, and antioxidant properties. Several clinical studies and randomized controlled trials have examined the effect of green tea mouthwash or extracts on gingival health. These studies have found that green tea preparations can reduce gingival bleeding, plaque accumulation, and inflammation when used as an adjunct to standard mechanical cleaning methods.

A 2012 randomized controlled trial published in the Journal of Indian Society of Periodontology reported significant improvements in gingival indices after the use of green tea mouth rinse compared to placebo. Other research has demonstrated that green tea catechins can inhibit the growth of periodontal pathogens such as Porphyromonas gingivalis and reduce the activity of matrix metalloproteinases implicated in tissue destruction.

While these results are promising, most studies highlight the need for larger and longer-term trials to confirm the benefits. Overall, there is moderate scientific evidence (rating 3) supporting the adjunctive use of Camellia sinensis extracts or rinses in improving gingivitis outcomes.