Antibiotic Properties of cannabis extracts applied to the surface of an infected area have been reported in both historical and modern times. Cannabinoids can kill bacteria that have proven resistant to commonly used antibiotics. In one documented case a researcher inadvertently injured his thumb during a dissection. The penicillin resistant infection became so severe that amputation seemed the only reasonable option. Amputation was unnecessary, however, because the infection was finally overcome with topical application of cannabidolic acid.
“Antibacterial actions have been demonstrated for CBD, CBG, and delta-9-THC. Incubation with delta-9-THC reduces the infectious potency of herpes simplex viruses.”
Most recently, investigators at Italy's Universita del Piemonte Orientale and Britain's University of London, School of Pharmacy assessed the antibacterial properties of five cannabinoids - THC, CBD (cannabidiol), CBG (cannabigerol), CBC (cannabichromine), and CBN (cannabinol) - against various strains of multidrug-resistant bacteria, including MRSA.
"All compounds showed potent antibacterial activity," authors determined. Researchers noted that cannabinoids showed "exceptional" antibacterial activity against EMERSA-15 and EMERSA-16, the major epidemic MRSA strains occurring in UK hospitals.
MRSA is a resistant variation of the common bacterium Staphylococcus aureus. It has evolved an ability to survive treatment with antibiotics. MRSA is especially troublesome in hospitalized patients with open wounds, invasive devices, and weakened immune systems. Hospital staff who do not follow proper sanitary procedures may transfer bacteria from patient to patient. According to a 2007 study published in the Journal of the American Medical Association, MRSA is responsible for more than 18,500 hospital-stay related deaths each year.
 Grinspoon, Marijuana Reconsidered. 3rd ed. San Francisco: Quick American Archives, 1971
 Grotenhermen, Russo, Cannabis and Cannabinoids: Pharmacology, Toxicology, and Therapeutic Potential . New York: The Hawthorn Integrative Healing Press, 2002, Grotenhermen, “Effects of Cannabis and the Cannabinoids.” Chapter 5, p. 60
 "Marijuana ingrediants may fight bacteria" Henrey Fountain, New York Times, September 9, 2008
 "Pot Compounds Reduce Multi-Drug-Resistant Infections, Study sayd Canabinoids Show "Exceptional" Antibacterial Activity Against MRSA", Paul Armentano, Deputy Director of NORML citing precinical data to be publsihed in the Journal of Natural Products See: www.NORML.org