system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What exactly does “catnip” do?
gpt
Catnip produces a chemical called Nepetalactone. When that enters a cats nose it triggers the production of endorphins in much the same way opiods do. There are basically happiness chemicals. So they basically just make the cat feel good, happy, and sometimes energetic. 

Fortunately, it does not seem to cause withdrawals or addiction in the same way. So get those kitties nice and high!