Carvacrol is a plant compound in oregano oil which gives the traditional pizza herb its distinctive aroma and flavour.
Scientists found that it is effective against highly infectious norovirus, the chief cause of vomiting and diarrhoea around the world.
The herb chemical strips the virus of its "armour", a tough outer protein coat, making it easier to destroy with other agents.
Lead researcher Dr Kelly Bright, from the University of Arizona in the United States, said: "Carvacrol could potentially be used as a food sanitiser and possibly as a surface sanitiser, particularly in conjunction with other antimicrobials.
"We have some work to do to assess its potential but carvacrol has a unique way of attacking the virus, which makes it an interesting prospect."
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Norovirus is a common cause of food-borne disease and a particular problem in nursing homes, hospitals, cruise ships and schools.
Although unpleasant, the infection usually passes in a few days. But it can pose a dangerous threat to some people with underlying medical problems.
Experiments showed that carvacrol acts directly on the capsid, the tough shell of proteins surrounding the virus that encloses its genetic material.
Because carvacrol attacks external elements of norovirus, it is unlikely to trigger the development of resistance, the scientists believe.
Used as a sanitiser it would be long-lasting, non-corrosive, fume-free and safe, say the experts.
They see it being especially useful in settings where people may be vulnerable to the effects of strong bleach or alcohol-based cleaners, such as care homes and schools.
However, the scientists stress that no amount of pizza consumption will protect anyone from norovirus.
Nor do they recommend taking concentrated carvacrol, which though non-toxic would cause burning and numbness of the tongue.
The research is published in the latest edition of the Journal Of Applied Microbiology.