Marijuana may be something of a wonder drug — though perhaps not in the way you might think.

Researchers in Italy and Britain have found that the main active ingredient in marijuana — tetrahydrocannabinol, or THC — and related compounds show promise as antibacterial agents, particularly against microbial strains that are already resistant to several classes of drugs.

It has been known for decades that Cannabis sativa has antibacterial properties. Experiments in the 1950s tested various marijuana preparations against skin and other infections, but researchers at the time had little understanding of marijuana's chemical makeup.

The current research, by Giovanni Appendino of the University of the Eastern Piedmont and colleagues and published in The Journal of Natural Products, looked at the antibacterial activity of the five most common cannabinoids. All were found effective against several common multi-resistant bacterial strains, although, perhaps understandably, the researchers suggested that the nonpsychotropic cannabinoids might prove more promising for eventual use.

The researchers say they don't know how the cannabinoids work, and whether they would be effective as systemic antibiotics would require much more research and trials. But the compounds may prove useful sooner as a topical agent against methicillin-resistant Staphylococcus aureus, or MRSA, to prevent the microbes from colonizing on the skin.