The ingredient which gives garlic its distinctive smell is the latest weapon in the battle to beat the hospital "superbug" MRSA.
Allicin occurs naturally in garlic
University of East London researchers found allicin treated even the most antibiotic-resistant strains of the infection.
MRSA (Methecillin-resistant Staphylococcus aureus) causes an estimated 2,000 deaths in UK hospitals each year.
Researchers are now testing allicin products in a six-month study.
Dr Ron Cutler and his team discovered the effectiveness of allicin in laboratory tests five years ago.
They found it can cure MRSA within weeks.
It is even effective against the newer strains which cannot be treated by the "last line of defence" antibiotics Vancomycin and Glycopeptides.
The team have developed a nasal cream, pills and soaps.
Initial trials have proved effective, so researchers will now test them in a six-month study of 200 volunteers including healthcare workers and patients.
The scientists hope the products will be used by people working in hospitals so they can prevent MRSA being passed on to patients, as well as the patients themselves.
MRSA organisms can live harmlessly in humans, carried in the nasal passages and on the skin, but they can cause fatal infections in immune-suppressed patients, the elderly, the young and those with surgical implants.
Dr Cutler told BBC News Online: "My aim would be to firstly work to try and reduce the carriage of MRSA amongst healthcare workers.
"But we would also hope to use allicin treatments for patients themselves."
He added: "The trials we have conducted so far show that this formulation is highly effective against MRSA, and it could save many lives.
"MRSA is causing a genuine crisis in our hospital system in Britain and worldwide. Antibiotics are increasingly ineffective, but we do have a powerful natural ally.
"Plant compounds have evolved over millions of years as chemical defence agents against infection.
"Garlic has been used in medicine for centuries, and it should be no surprise that it is effective against this very modern infection."
Deborah Brown, 34, from Rainham in Kent, contracted MRSA after a major spinal operation in November 2000.
Painful wounds on her spine failed to heal for two years, despite using the antibiotics and creams currently available.
But within two months of using the allicin creams and pills, her MRSA had virtually cleared and the wounds had begun to heal.
She said: "The effect of the treatment was dramatic - I am making a good recovery - but it was really awful at the time.
"Having weeping wounds on my back that never healed was incredibly painful and I became increasingly depressed as the MRSA didn't respond to repeated courses of antibiotics.
"If my case helps to show that allicin works against MRSA then I am glad that something good might come of it."
The research is to be published in the Journal of Biomedical Science next year.