Tobacco use is responsible for most cases of chronic periodontitis in developed nations. Cigarette smoke exerts a profound effect on microbial interactions within dental plaque; promotes infection with key periodontopathogens, including Porphyromonas gingivalis; and suppresses the innate and adaptive arms of the immune response to gingival biofilms. Cannabis use is also a dose-related risk factor for plaque-induced chronic periodontitis. How cannabis exposure may predispose to this periodontal diseaseis largely unknown. Our recent data suggest that phytocannabinoids(cannabidiol [CBD]; cannabinol [CBN]; and tetrahydrocannabinol [THC]) are each more toxic to oral bacteria and innate cells than is cigarette smoke. Further, while these marijuana-derived molecules appear to be potent suppressors of innate immunity, their mechanisms of action may differ from those ascribed to tobacco-mediated dampening of the inflammatory response to bacteria. These findings are discussed in the context of the etiology of chronic periodontitis and- as marijuana and tobacco are often simultaneously consumed - the need for further research on tobacco/marijuana as composite insults.