A 1,000-year-old Anglo-Saxon recipe can kill up to 90 percent of MRSA bacteria. Here is what Bald’s eyesalve is and why it matters.

The recipe comes from Bald’s Leechbook, a 10th-century medical text in the British Library. It was meant to treat a sty, an infection of the eyelash follicle.

The ingredients are simple: garlic, onion, wine and bovine bile. They are mixed, then left to stand in a brass vessel for nine days before use.

In 2015, microbiologist Freya Harrison of the University of Nottingham recreated the recipe faithfully. Lab tests showed it wiped out up to 90 percent of MRSA. It also destroyed biofilms, the sticky bacterial colonies that antibiotics struggle to penetrate.

Crucially, no single ingredient worked alone. The combination was what mattered. New research shows the brew attacks microbes in multiple ways: it damages cell membranes, disrupts hundreds of bacterial genes and blocks the communication bacteria use to coordinate.

For bacteria to survive, they would have to mutate several targets at once, which is far harder than resisting one drug.

Antibiotic-resistant infections kill over a million people a year. Ancient texts may hide more such mixture-based treatments.