What's the difference between aspirin and acetaminophen?

To entirely different drugs that in part treat similar symptoms. Both reduce fever and pain while aspirin thins your blood and helps some with inflammation. Aspirin is dangerous to give to children under certain conditions and the alternative is acetominophen.

The difference was in mechanism of action and in indication.
Where as acetaminophen act as antipyretic and analgesic due to inhibition of COX3.
Aspirin act by inhibition of COX1 and use as antipyretic and analgesic and anti inflammatory.
There is also differences in side effect where aspirin more irritating to the stomach than acetaminophen wich in turn has more liver toxicity than aspirin.
Aspirin also given as blood thinner while acetaminophen was not.