Reverse pharmacology is when scientists take a different approach to finding new drugs. Instead of starting from scratch and making a new substance, they start with one that already exists and try to figure out what it does and how it works in the body.
Picture your toybox. Normally, you start with a bunch of Lego pieces and build a tower. But reverse pharmacology starts with a toy you've already built and tries to take it apart and make something else with the same pieces.
This approach can be helpful because sometimes scientists stumble upon a toy that seems interesting but they don't know what it's supposed to do. So they take it apart, see how it's put together, and learn more about how it works. Then they can use that knowledge to build something better or to fix something that's broken.
We can also think of this like a puzzle. Instead of starting with a blank canvas and drawing a picture from scratch, scientists start with a finished puzzle and take it apart piece-by-piece to understand how it was made. They can then use that knowledge to create a new puzzle or to fix one that's broken.
In summary, reverse pharmacology is like taking apart an old toy or puzzle to learn how it works and then using that knowledge to make something better or fix something that's broken.