Welcome to brain Stuff from How Stuff Works. Hey brain Stuff, I'm Lauren Vogelbaum, and today's episode is a brain Stuff classic, How does Aspirin Work? I wrote this one for our YouTube channel a while back while I was going through a pain research phase, which yes, is just about as goth as it sounds. It was performed for the podcast by our former host, Christian Saga. Let's dive in, Hey brain Stuff. It's Christian Sager here. There are lots of ways to numb yourself to the minor aches and pains
that we humans accrew in our daily lives. But today we're talking about aspirin. Why aspirin, Because although aspirin as we know it has only existed since the late eighteen hundreds, the plant that it was originally derived from, willow, is
probably the oldest known pain killer in history. Records of people using willow leaves to relieve pain and fevers stretch back six thousand years to ancient Assyria and sumer Willow was also put to use in ancient Egypt, Babylon, and China, and Hippocrates thought it was pretty rad especially for pain
during childbirth. In the seventeen and eighteen hundreds, scientists worked on identifying, extracting, and purifying the active ingredient in willow, which turned out to be a chemical they called salison, which they further discovered your digestive system changes into salacilic acid, which is what reacts with stuff in your body to relieve pain, reduced fever, and swelling. More on how all that works In a second, but first salacilic acid. It
was a pharmacological superstar. German chemists figured out how to synthesize it on an industrial scale in the eighteen seventies, effectively ending millennia of willow powder use. But it had
its drawbacks. Lots of patients couldn't stomach it literally, it was really hard on the stomach lining The son of one such patient, a chemist with Friedrich bear in Company by the name of Felix Hoffman, thought it might be less irritating if it was less acidic, so Hoffman converted it to what bear in Company dubbed aspirin in eight Aspirin has become the popular and less ridiculous to pronounce name for Hoffman's chemical compound, a setal silic acid or salicylate.
It works as humanity finally figured out in the nineteen seventies by preventing yourselves from using cyclo oxygen ase to to create prostaglandins. And don't worry, I'm about to unpack all of those words. Let's start with the idea that lots of pain is useful evolutionarily speaking, when you feel pain due to an injury like a burn or a twisted ankle, it prompts you to take your hand away from that hot thing real quick, or to keep your weight off the ankle until it heals. It's it's useful, right.
Pain from an injury to anything but the nervous system is called no susceptive pain. After specialized sensory neurons located throughout your body called no susceptors, They alert your brain to damage. With the help of the damaged tissue itself, cells in the hurt areas start producing enzymes that work together to create a few signal chemicals, including those prostaglandins I mentioned a minute ago. Prostaglandins tell your no susceptors, no, hey, seriously,
there is a problem here. They make your no susceptors increase the signal to your brain. You feel the pain more acutely now Prostaglandins are also one of the chemicals that cause inflammation in the tissue around a wound. They make your blood vessels expand, flooding the damaged tissue with all the immune systems stuff your body sends to protect the wound from infection and to help it to heal. All of this is great right up until it isn't.
After a certain point. You don't need continual acute pain as a reminder that you're injured. We know, and some non susceptive pain and swelling is warning us about stimuli that we can't easily avoid, like headaches, arthritis, or period cramps. In the case of arthritis, that inflammation can even cause more damage in the long run. Here's where aspirin swoops
in to save the day. When you take aspirin, it's absorbed by your digestive tract into your blood stream, which takes it throughout your body, including places where cells are excreting the enzymes necessary to produce prostaglandins. Molecules of aspirin lock up with one of those enzymes, cyclo oxygenase too.
Once a molecule of cyclo oxygenase two is locked into a molecule of aspirin, it can't help create prostaglandins, which means fewer prostaglandins, which means that the pain signals to your brain don't increase as much and the tissue in the area doesn't swell as much. Hey, thanks thousands of years of science. Today's episode was produced by Tyler Klang.
If you miss Christian and want to hear more from him, check out his pop culture podcast super Context, And of course, for more on this and lots of other anti inflammatory topics, visit our home planet, how stuff works dot com.