What is the difference between a doctor and a witch? Or between a physician and an alchemist? During a large part of our history, those distinctions often came down to gender. If an illiterate old woman mixed up strange herbs and used it to alleviate someone's illness, it had to be magic, or worse, witchcraft. But that deep knowledge of plants and chemical processes that was handed down orally was actually science, although it appeared to be supernatural to people who didn't understand it. And it's hard to prove these days because most of it wasn't written down.
But from analyzing the few of these "magic potions" and "spells" that were written down, historians and scientists can see why many of them worked. You don't need a formal education to remember that St. John's wort was good for inflammation, or that some plants had to be distilled to isolate the active ingredients. If it worked, you were a witch. If it didn't, well, then you were an evil witch. Read about some of those ancient potions and poisons that really did work as intended, and the people who managed to harness them at Chemistry World. -via Strange Company