What do you get when you mix garlic and onions (or leeks), wine, and cow bile together, and brew it in a brass container before letting it sit for nine days? Besides a nasty mixture, you also get an old Anglo-Saxon remedy for a stye, an infection of the eyelash follicles. Researchers from the University of Nottingham in the UK have now revived this thousand-year-old remedy, and found it’s surprisingly good at eliminating the bacteria responsible for styes; one that’s become increasingly resistant to current antibiotics.

The 1,000-year-old Medieval recipe was found in Bald’s Leechbook, an old leatherbound book that’s considered one of the oldest medical textbooks in existence. Curious to see how effective the “potion” was against the bacteria Staphylococcus aureus, they recreated it. But while they found it was effective in treating styes, they also found, perhaps more importantly, that it could kill methicillin-resistant S. aureus (MRSA) in artificial wounds. The drug-resistant superbug causes over 80,000 severe infections and 11,000 deaths each year, according to the Centers for Disease Control and Prevention (CDC), with most emerging in health care settings.

“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,” said study leader Freya Harrison, a microbiologist at the university, according to CBS. “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 tissue.”

The team recreated four batches of the salve, which becomes creamy after nine days, using fresh ingredients. They then applied it to the artificial wounds in both full-strength and diluted form — as well as treating each wound with individual ingredients. They found that only the full-strength form of the salve worked, and when it did, it killed all but one out of 1,000 cells of MRSA. It was even powerful enough to break down MRSA biofilms, naturally drug-resistant cellular communities.

Antibiotic-resistant bacteria are a growing concern not only in the U.S. but throughout the world. As more people unnecessarily use antibiotics, their numbers will grow, and previously eradicated disease could reemerge. Over two million people in the U.S. alone become infected with one of these superbugs each year, and 23,000 die from them. For this reason, the Obama administration recently released an internationally focused action plan to prevent their growth last week.

"The rise of antibiotic resistance in pathogenic bacteria and the lack of new antimicrobials in the developmental pipeline are key challenges for human health," Harrison said. "There is a pressing need to develop new strategies against pathogens because the cost of developing new antibiotics is high and eventual resistance is likely."