Green tea has been shown in individual studies to be effective in reducing plaque and its use against gingivitis. Therefore, the aim of this study was to systematically review available literature on green tea catechin. The systematic literature search was performed using electronic databases in CINAHL, Cochrane Library, MEDLINE, PubMed and Scopus until January 2017. The PRISMA criteria were applied and a research question was posed according to PICO: “In patients with gingivitis (population), what is the effect of green tea catechins-containing mouthwash (intervention and comparison) on plaque accumulation and gingival inflammation (outcome)?”. Out of 187 titles identified by the search strategy, five were suitable for meta-analyses. These five studies were undertaken on a predominately Asian population. Plaque (PI) and Gingival Index (GI) were compared at endpoint and with respect to the change throughout the study (baseline-endpoint). The results from the meta-analysis indicated that green tea and chlorhexidine (CHX) resulted in lower PI compared to placebo while there was no significant difference between CHX and green tea, either at endpoint or over time. In addition, there was little evidence of side effects with green tea mouthwash. Green tea mouthwash may be a viable alternative to CHX, especially for long-term use. However, due to the very heterogeneous data and the risk of bias, this evidence should be interpreted with caution. Further clinically controlled studies with a longer observation period are required
