Many bacterial infections possess multi-drug resistance. Among the most significant of these bacteria is methicillin-resistant Staphylococcus aureus, more commonly known as MRSA or “the superbug.” This bacterium is resistant to standard antibiotics, including penicillin. According to the Journal of the American Medical Association, MRSA is responsible for nearly 20,000 hospital-stay-related deaths annually in the United States.
Cannabinoids are acknowledged to possess antibacterial and antifungal properties, and topical preparations of the plant were initially investigated for these purposes nearly a century ago. In 2008, investigators at Italy’s Universita del Piemonte Orientale and Britain’s University of London, School of Pharmacy, assessed the germ-fighting properties of five separate cannabinoids against various strains of multidrug-resistant bacteria, including MRSA. They reported that all of the compounds tested showed “potent antibacterial activity” and that cannabinoids were “exceptional” at halting the spread of MRSA.
Other studies have reported that non-cannabinoid constituents in the plant, such as terpenoids, also possess antibacterial properties against MRSA and malaria.[5-7]
Ethanol-based tinctures containing crushed cannabis leaves have also been documented to inhibit MRSA growth.
Recent studies have also demonstrated that cannabinoids are effective in reducing the colony count of dental bacteria, leading investigators to opine in favor of “the potential of cannabinoids in developing efficient and safer mouthwash products and next generation oral care products.”
Clinical trials regarding the use of cannabinoids as antibacterial and antimicrobial agents have been recommended, but are yet to be conducted. Experts opine, “Cannabis sativa … represents an interesting source of antibacterial agents to address the problem of multidrug resistance in MRSA and other pathogenic bacteria.”
 Klevens et al. 2007. Invasive methicillin-resistant Staphylococcus aureus infections in the United States. Journal of the American Medical Association 298: 1763-1771.
 Radwan et al. 2009. Biologically active cannabinoids from high-potency Cannabis sativa. Journal of Natural Products 72: 906-911.
 Izzo et al. 2009. Non-psychotropic plant cannabinoids: New therapeutic opportunities from an ancient herb. Trends in Pharmaceutical Sciences 30: 515-527.
 Appendino et al. 2008. Antibacterial cannabinoids from cannabis sativa: a structure study. Journal of Natural Products 71: 1427-1430.
 Radwan et al. 2008. Non-cannabinoid constituents from a high potency cannabis sativa variety. Phytochemistry 69: 26727-2633.
 Ahmed et al. 2015. Minor oxygenated cannabinoids from high potency Cannabis sativa L. Phytochemistry 117: 194-199.
 Ethan Russo. 2011. Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects. British Journal of Pharmacology 163: 1344-1364.
 Chakraborty et al. 2018. Antimicrobial activity of Cannabis sativa, Thuja orientalis, and Psidium guajava leaf extracts against methicillin-resistant Staphylococcus aureus, Journal of Integrative Medicine 5: 350-357.
 Stahl and Vasudevan. 2020. Comparison of Efficacy of Cannabinoids versus Commercial Oral Care Products in Reducing Bacterial Content from Dental Plaque: A Preliminary Observation. Cureus 12 [open access journal]
 Vasudevan and Stahl. 2020. Cannabinoids infused mouthwash products are as effective as chlorhexidine on inhibition of total-culturable bacterial content in dental plaque samples. Journal of Cannabis Research 23 [open access journal].
 Appendino et al. 2008. op. cit.