The intersection of traditional beverage consumption and oral health science has produced a growing body of research on Camellia sinensis (tea) and Coffea arabica (coffee), but Ilex paraguariensis — despite being the third most consumed caffeinated beverage on Earth — has received comparatively little systematic attention from dental researchers. A comprehensive review published in May 2025 aims to close this gap by synthesizing the available evidence on yerba mate's effects across the full spectrum of oral health conditions, from dental caries and periodontal disease to oral cancer.
Bioactive Arsenal: What's in the Leaf
The review identifies the key bioactive compounds responsible for yerba mate's oral health effects: polyphenols (including chlorogenic acid, caffeoylquinic acid derivatives, and flavonoids), caffeine, saponins, and tannins. These compounds exhibit antioxidant, anti-inflammatory, and antimicrobial properties that — according to the accumulated in vitro and in vivo evidence — interact with oral tissues and microbial communities in multiple clinically relevant ways.
Antibacterial Effects: Targeting the Pathogens
The most robust evidence concerns yerba mate's antimicrobial activity against oral pathogens. Multiple studies cited in the review demonstrate that yerba mate extracts inhibit the growth of Streptococcus mutans, the primary bacterial species responsible for dental caries, and Porphyromonas gingivalis, a keystone pathogen in periodontal disease. The mechanisms appear to involve both direct bactericidal action and disruption of biofilm formation — the structured microbial communities that adhere to tooth surfaces and resist removal by saliva and mechanical cleaning.
Beyond Bacteria: Cancer Inhibition and Tissue Regeneration
Perhaps the most provocative finding in the review concerns yerba mate's effects on oral cancer cells. Several in vitro studies report that yerba mate extracts inhibit the proliferation of oral squamous cell carcinoma and other oral cancer cell lines, with the antiproliferative effects attributed primarily to chlorogenic acid and its metabolites. Additionally, a September 2025 study investigated yerba mate's role in reducing oxidative stress and bone resorption in apical periodontitis — a chronic inflammatory condition affecting the root tips of teeth — and demonstrated anti-osteoclastogenic and immunomodulatory effects on oral stem cells and macrophages, suggesting therapeutic potential in mitigating inflammatory oral diseases.
Clinical Translation: What's Missing
The review's authors acknowledge a critical gap: the vast majority of the evidence comes from laboratory studies (in vitro or animal models), not from clinical trials in human populations. The leap from demonstrating that a plant extract kills bacteria in a petri dish to proving that drinking mate prevents cavities in living humans is substantial and has not yet been definitively bridged. The authors call for randomized controlled clinical trials comparing long-term oral health outcomes between mate consumers and matched controls — studies that would require multi-year follow-up and large sample sizes but would provide the evidence needed to support clinical recommendations.