In 1700s England, there lived a so-called witch (or “botanist” or “gypsy,” depending on which account you read) who figured out how to cure heart failure using a plant-based remedy. Despite working well outside the margins of medicine at the time, this woman, known to the history books only as “Mrs. Hutton,” was succeeding where the best doctors were failing.

The medical community at the time discovered Hutton from a patient who gave up on the failures of doctors to treat their heart failure, and defected to the witch’s care. When the patient, fully recovered, told their physician, William Withering, about Hutton’s miracle remedy, Withering left Stafford and took the 30 miles (50 km) journey to the witch’s home in Shropshire, and asked her for some of her concoction to study himself.

Witch’s brews that modern science believes in

Withering hypothesized that the active ingredient in Hutton’s remedy was the foxglove plant. He tested this by administering dried, crushed foxglove leaves to over 160 patients, and wrote up his findings (pdf) in 1785, noting that it was particularly useful for those who had developed scarlet fever or strep throat, which can lead to heart damage when untreated. Today, we know even more details about why Hutton’s remedy worked: digoxin, a compound found in foxglove is still used as the active ingredient in some heart and blood pressure medications.

Over the years, modern Western medicine has taken many remedies from all kinds of alternative forms of medicine, including witchcraft, according to Smithsonian. Witches used willow bark to treat inflammation; the compound used in aspirin today was developed based on a precursor chemical found in the willow tree. They used garlic for ulcers; garlic has since been found (paywall) to slightly lower cholesterol and partially block the formation of platelets, which can cause blot clots. So-called “flying ointment”—a “magical aid” with hallucinogenic effects—contained henbane, nightshade, and mandrake. Henbane contains hyoscine, which is now used in lower doses to treat motion sickness and stomach cramps. Nightshade contains atropine, a muscle relaxant that is sometimes used to calm patients going into surgery and to treat nerve-gas poisoning.

How witches got their name and reputation

As Salon notes in an essay about the 2010 revision of Witches, Midwives and Nurses, witches developed their name and evil reputation in the context of European medieval class struggles, the continuing domination of the Christian church, and a burgeoning field of study that would become what we now think of as the Western scientific tradition. Early medical establishments that arose in the 1200s in Europe banned women from practicing medicine. For centuries, only doctors—nearly all of them white and male—were deemed credible medical practitioners; women could only be their assistants.

The idea that a woman could offer cures that male doctors couldn’t was seen as so preposterous, it had to be be magic.

But doctors were expensive. Poor people often only had one other option: women who practiced medicine or midwifery illegally. For all their trouble, religious and civic authorities labeled these women as “Satanic” (or tried them for practicing illegal medicine). According to Barbara Ehrenreich and Deirdre English, the authors of Witches, Midwives, and Nurses, this was in part because their work saving the lives of the poor undermined the advice the Christian church gave the severely impoverished at the time: to simply accept death.

Ehrenreich and English also note that authorities frowned upon any women meeting in large groups, for fear that they were creating covens to worship Satan. These women, the Christian authorities said, were likely witches. (Most likely, Ehrenreich and English say, the women were probably meeting to share what they’d learned in their personal health care practices.) Ironically, one of the biggest grievances medicine had with witches was that they were good at their job. The idea that a woman could offer cures that male doctors couldn’t was seen as so preposterous, it had to be be magic.

Witches probably couldn’t tell you scientifically how their cures worked; they just knew that their therapies made people feel better. But neither could a lot of the early practitioners of Western medicine. Digoxin itself wasn’t even isolated as the active ingredient from foxglove until the 20th century, almost 200 years after Withering discovered the plant’s use. Even today, although rigorous and extensive clinical trials are required to show that a drug is safe and effective before it is approved for use, there is no requirement to show exactly how it works—as long as it heals patients.