When we generally think of medicine before the 20th century, we usually imagine doctors sticking leeches on people or using fire to cure a sore shoulder. But they must’ve been doing something right, otherwise humans would not be around today. Scientists in Britain found out that medieval doctors were effective in their time, and they might also be able to help us out today.

Researchers at the University of Nottingham found a 1,000-year-old textbook that may contain a recipe to help fight Methicillin-resistant Staphylococcus aureus, also known as MRSA. The bacterial infection is particularly dangerous because of its ability to resist antibiotics, which can cause outbreaks in hospitals and nursing homes in a very short period of time. But scientists seem convinced that this new recipe can possibly be the cure.

After finding the book, Viking Studies professor Christina Lee translated it from Old English and compiled the recipe. The remedy contains cow’s stomach and allium, a plant in the garlic family, and is mixed in a brass vessel. Scientists at the university then created the concoction trying to follow the instructions exactly.

It worked. About 999 out of 1,000 MRSA bacterial cells were killed when treated with the medieval formula. They then used the treatment on mice, where it killed 90 percent of MRSA bacteria. Nottingham microbiologist Freya Harrison told the LA Times she was “absolutely blown away” with the results.

To put this in perspective, Kendra Rumbaugh, a professor of surgery at Texas Tech University’s School of Medicine, also said to the Times, “We haven to tested a single antibiotic or experimental therapeutic that is completely effective,” and this medieval formula is either as effective “if not better than the conventional antibiotics we used.”

Somehow a bunch of people who thought that only witches could float in water may have solved one of the biggest mysteries facing modern medicine. The University of Nottingham released a video with more details on the project:

And to think they did this all without the iPhone 6.