system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If you accidentally swallow something while breathing in, does it go into your lungs? If so, would it just stay there for ever? If not, what stops it?
gpt
It depends on what you inhale, and if it actually makes it down inside the lungs proper. Typically, if it is food, you'll either cough it up eventually, or absorb it.

For non-organics, you may cough it up, or need to have it extracted by a doctor. If you don't see it actually come out, you should see a doctor, as if it gets all the way into your lungs, it is difficult for the body to remove on its own.

There have been cases of children inhaling small objects by accident only to find them still in their lungs well into adulthood.

Inhaling an object is a significant source of foreign bacteria, and can lead to pneumonia.

TLDR: we are pretty good at keeping stuff from actually going into our lungs, but fairly terrible at undoing it if we succeed.