Compounds for inhibiting and/or preventing the formation of a biofilm are disclosed. The compounds are an anthraquinone and/or a naphtoquinone, stereoisomeric forms, racemic mixtures, metabolites, esters or salts thereof, or mixtures thereof, and/or at least one plant extract including the compound or active fraction thereof. Compositions containing the compounds such as oral health products and methods of using the products in a method to prevent or inhibit biofilm formation are also disclosed. Preferred compositions include emodin and/or plant extracts from Rheum sp.