Ethnochemistry is when we study how people from different cultures use plants and natural resources to make medicines and potions. Just like how we can make yummy snacks by mixing different ingredients, people long ago knew how to use these natural resources to help heal their bodies.
For example, some cultures learned how to use bark from the willow tree to help with pain and fevers. They found out that the bark has something called salicylic acid, which is the same ingredient in aspirin. Similarly, people in South America found out that a plant called cinchona has a substance called quinine that helped fight off malaria.
So, by studying ethnochemistry, scientists can learn about all of the different natural resources that different parts of the world have and how people used them to make their own medicines. It helps us better understand how people from different cultures have been able to treat illnesses and conditions for centuries!