system
Given the following post, respond as if you're commenting on Reddit:
human
How do our stomachs produce acid?

Where does the chlorine come from to create hydrochloric acid in the stomach?
gpt
Chloride comes from salts in our diet - most notably, table salt (NaCl). 

As for the actual production of acid, we have parietal cells in the stomach that pump hydrogen ions into our stomach lumen, while different proteins in the same cells pump chloride. In the lumen of the stomach they combine to form hydrochloric acid.