Guava (Psidium guajava) has a longstanding history of use in traditional medicine for oral health, particularly for supporting gum health. This traditional use is primarily based on the antimicrobial and anti-inflammatory properties of guava leaves and fruits. Scientifically, several studies have investigated guava extracts for their effects on oral microbes and gum inflammation. Research indicates that guava leaf extracts possess significant antibacterial activity against pathogens that contribute to periodontal disease, such as Porphyromonas gingivalis and Streptococcus mutans. In addition, guava leaves contain flavonoids, tannins, and other phytochemicals known to reduce inflammation and oxidative stress in oral tissues.

A few small clinical studies and randomized controlled trials have evaluated guava mouth rinses or topical applications for their effects on gingivitis and plaque accumulation. These studies generally report improvements in gum health, reduced bleeding, and decreased inflammation compared to controls. However, the number of high-quality, large-scale clinical trials remains limited, and most evidence is preliminary or based on in vitro and animal studies.

Overall, there is scientific support for the use of guava, especially guava leaf extract, in supporting gum health due to its antimicrobial and anti-inflammatory actions. Nevertheless, more robust human clinical data are needed to fully validate its efficacy and determine optimal dosages and formulations for routine use in oral hygiene.