If you could treat a serious health condition by ingesting something poisonous or dangerous, would you do it?

You actually might be doing that already, if the history of nitroglycerin is any indication. A video from SciShow explains the origin of that explosive material, used in dynamite, and how it became a heart medication. According to host Michael Aranda, in small doses your body will convert it into a compound called nitric oxide that will relax your blood vessels and lower your blood pressure. In larger amounts, it makes a big boom.

Boom. Credit: Mythbusters

“Depending on how you use it, it could blow you to pieces or it could save your life,” Aranda says. That volatility is because of nitroglycerin’s makeup: once an explosive reaction begins, everything it needs to sustain the explosion is within it — it’s not as mortally weak as fire, which needs oxygen from the air to keep it going.

Read: How Dangerous Is Your Heartburn

The development of a heart medication from nitroglycerin is not, however, the first time doctors have used potentially harmful materials to treat their patients. Arsenic has been found to cause cancer and other health problems, yet it is a current treatment for a rare type of blood cancer, and during Victorian times, it was used to treat syphilis. And that’s just one of the many poisons that double as medicine.

Inconceivable! Credit: The Princess Bride

Throughout the ages, doctors have also used poop — yes, poop — to heal their patients. That includes excrement from donkeys, dogs, crocodiles, gazelles and many more. They were used for all sorts of ailments, from nosebleeds to serious diseases, and even as a form of birth control. Today, as gross as it sounds, physicians still use poop for medicinal purposes: fecal transplants, in which stool from a donor is placed in a patient with a digestive or autoimmune disease, are a way to add beneficial gut bacteria that fights infection.

See also:

Eat Chocolate for a Healthy Heart

When Your Heart Turns Into a Bone