The remedy, made as a brew by ancient physicians, was found in a manuscript in the British Library and was used by the Anglo-Saxons to treat eye infections.
The book, Bald's Leechbook, was found by an academic at Nottingham University - who then invited microbiologists to test the remedy.
They say the results are "astonishing."
Laboratory studies found it killed 90% of drug-resistant MRSA bacteria infecting wounds in laboratory mice.
The brew involves bile from a cow's stomach, two species of the garlic family and wine. It has to be made by a specific technique in a brass vessel.
The researchers say not just the ingredients but the technique may be critical to creating chemicals that can destroy MRSA.
They reported their findings yesterday to the conference of the Society for General Microbiology in Birmingham, UK, yesterday.
Microbiologist Dr Freya Harrison said: “We thought that Bald’s eyesalve might show a small amount of antibiotic activity, because each of the ingredients has been shown by other researchers to have some effect on bacteria in the lab – copper and bile salts can kill bacteria, and the garlic family of plants make chemicals that interfere with the bacteria’s ability to damage infected tissues. But we were absolutely blown away by just how effective the combination of ingredients was.
"We tested it in difficult conditions too; we let our artificial infections grow into dense, mature populations called biofilm’, where the individual cells bunch together and make a sticky coating that makes it hard for antibiotics to reach them.
"But unlike many modern antibiotics, Bald’s eye salve has the power to breach these defences.”
Fellow researcher Dr Steve Diggle said: “When we built this recipe in the lab I didn't really expect it to actually do anything. When we found that it could actually disrupt and kill cells in S. aureus biofilms, I was genuinely amazed. Biofilms are naturally antibiotic resistant and difficult to treat so this was a great result.
"The fact that it works on an organism that it was apparently designed to treat (an infection of a stye in the eye), suggests that people were doing carefully planned experiments long before the scientific method was developed.”
Dr Cristina Lee, an expert in Viking studies, said: “Medieval leech books and herbaria contain many remedies designed to treat what are clearly bacterial infections (weeping wounds/sores, eye and throat infections, skin conditions such as erysipelas, leprosy and chest infections).
"Given that these remedies were developed well before the modern understanding of germ theory, this poses two questions: How systematic was the development of these remedies? And how effective were these remedies against the likely causative species of bacteria?
"Answering these questions will greatly improve our understanding of medieval scholarship and medical empiricism, and may reveal new ways of treating serious bacterial infections that continue to cause illness and death.”
Image copyright: The British Library Board (Royal 12 D xvii)
The nano-needles are made from biodegradable silicon that would dissolve harmlessly in the body. The transmit DNA and other nucleic acids into cells, enabling them to be re-programmed.
So far the needles have been used to generate new blood vessels in laboratory mice.
The researchers say their first application in humans would be to generate new blood vessels to improve transplants or implants of artificial organs.
Researcher Professor Molly Stevens, of Imperial College, London, said: “It is still very early days in our research, but we are pleased that the nanoneedles have been successful in this trial in mice.
"There are a number of hurdles to overcome and we haven’t yet trialled the nanoneedles in humans, but we think they have enormous potential for helping the body to repair itself.”
Fellow researcher Dr Ciro Chiappini said: “If we can harness the power of nucleic acids and prompt them to carry out specific tasks, it will give us a way to regenerate lost function. Perhaps in the future it may be possible for doctors to apply flexible bandages to severely burnt skin to reprogram the cells to heal that injury with functional tissue instead of forming a scar.
"Alternatively, we may see surgeons first applying the nanoneedle bandages inside the affected region to promote the healthy integration of these new organs and implants in the body. We are a long way off, but our initial trials seem very promising.”
Biodegradable silicon nanoneedles delivering nucleic acids intracellularly induce localized in vivo neovascularization Nature Materials 30 March 2015
Even in the most polluted areas of a city, it may be healthier to be active outside than sitting indoors, according to Danish researchers.
The findings come from a major study of more than 50,000 people in two Danish cities, Aarhus and Copenhagen, who took part in research on their lifestyles in the 1990s.
By 2010, some 5,500 people had died and the latest study links death rates to pollution and activity levels.
The study found 20% fewer deaths among those who lived active lives than those who did not - even when they lived in heavily polluted neighbourhoods.
The findings have been published in Environmental Health Perspectives.
Researcher Professor Zorana Jovanovic Andersen, from Copenhagen University, said: "Air pollution is often perceived as a barrier to exercise in urban areas. In the face of an increasing health burden due to rising physical inactivity and obesity in modern societies, our findings provide support for efforts in promoting exercise, even in urban areas with high pollution.
"However, we would still advise people to exercise and cycle in green areas, parks, woods, with low air pollution and away from busy roads, when possible."
Environmental Health Perspectives 30 March 2015
A study found that 20% of teenagers have used the devices.
And for 16%, e-cigarettes provided their first experience of smoking. Another 23% may have turned to the devices because they tried cigarettes and did not like them.
The findings come from a survey of more than 16,000 school-aged teenagers in the north west of England.
The research at Liverpool John Moores University, UK, was published in BMC Public Health.
They found a link between the use of e-cigarettes and other risk behaviour, such as binge drinking and involvement in violence after drinking.
The findings will sharpen the debate on e-cigarettes which are marketed as a safer substitute for smokers. Companies are not allowed to market them to teenagers.
Researcher Mark Bellis said: "Our research suggests that we should be very concerned about teenagers accessing e-cigarettes. While debate on e-cigarettes has focused largely on whether or not they act as a gateway to tobacco cigarette use, e-cigarettes themselves contain a highly addictive drug that may have more serious and longer lasting impacts on children because their brains are still developing.
"Despite being practically unheard of just a decade ago, e-cigarettes are now widely available, heavily promoted yet weakly regulated and our study found that one in five 14-17 year old school children in the North West has accessed them. Such rapid penetration into teenage culture of what is essentially a new drug use option is without precedent.
"Of particular concern is our finding that teenage ex-smokers who accessed e-cigarettes were outnumbered by those who had never smoked but simply decided to experiment with what might be packaged to look like a safe attractive product but actually contains a highly addictive drug."
Associations between e-cigarette access and smoking and drinking behaviours in teenagers BMC Public Health 30 March 2015; doi:10.1186/s12889-015-1618-4 [abstract]