Periodontitis is a biofilm depended oral infection. It leads to inflammatory destruction of periodontal tissues and if left untreated to tooth loss. Porphyromonas gingivalis (P.g.) is one of the major pathogens associated with the onset and progression of periodontitis. Previous in vitro studies have shown that a proanthocyanidin-enriched extract from Rumex acetosa L. inhibits the adhesion of P.g. and acts in a cytoprotective manner. Since the the bacterial adhesion to oral mucosa cells is a pivotal step for the P.g. mediated tissue destruction, its inhibition may be helpful in preventing the colonization with P.g. or its eradication in P.g. infected patients. Therefore, the aim of this controlled, randomized and double blinded study was to analyze the effects of a Proanthocyanidin-enriched extract from Rumex acetosa L. on the intraoral colonization with Porphyromonas gingivalis in individuals harboring P.g. intramurally.