system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do we feel the urge to keep throwing up even if there is nothing left?
gpt
It's because of the physiological mechanisms involved in throwing up.

When you first start, it's in response to the body trying to expel something. The muscles around your stomach contract and squeeze it to propel the contents out (there are other elements involved, but they're not relevant to the question).

After a while these muscles start spasming despite the fact that the stomach is empty, which is what leads to the continued retching afterwards.