Definition from Wiktionary, the free dictionary
to act on (phrasal verb)
- To act decisively on the basis of information received or deduced.
- The policeman decided to act on the tip from his informant.
- To take action against something.
- World leaders have repeatedly stated that we must act on climate change.
- (medicine) To affect something.
- Different drugs act on different parts of our body in many different ways.