Re: I would please like to know why salicylic acid irritates the stomach.

Hi Rica, do you mean aspirin, (you may have a different name for it in the 
US), comes originally from salicylic acid? 
Aspirin is an antagonist meaning that it blocks the action of 
prostaglandins which become active at injury/trauma sites. Prostaglandin 
is also responsible for controlling gastric acid release so if aspirin is 
taken for too long, the stomach lining will be compromised. This can cause 
intenal bleeding.The problem will stop when a person stops taking the drug.
Hope this is OK if you need to know more I can be more detailed.