I had an experiment. A test tube containing small portion of aspirin was prepared. NaOH was added to the solution, and then HCl was added. when I mixed FeCl3 with the solution, the solution turned intense purple. This result is the positive test for phenols. And why does this result proves that the aspirin is active in intestine? I cannot understand. I thought the aspirin is most active in stomach, because I though the acid converts aspirin to salicylic acid?