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Name: Wildman Jackson
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How does Aspirin, or any other pain reliever, "know" where to do to do its job? (I.e. if you take aspirin for a headache, the aspirin moves through the blood, and then somehow alleviates the pain there, while not affecting other areas.) How does this pain relieving process work once it gets there?

It doesn't. Any drug like aspirin does what it does wherever it goes, although some of its effects may be specific because its real target molecules aren't everywhere. But the basic answer as to why it only acts on your headache, is that you only have a headache. That's where you have pain, so that's where it relieves pain. Its effects elsewhere aren't felt by you because you don't have pain there. If you did, the aspirin would work there, too.


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