When you have a headache, and take aspirin, how does the medicine know where to go?

Aspirin thins out your blood relieving not only headaches, but most pain caused by swelling and inflammation.

When you have a headache, and take aspirin, how does the medicine know where to go?sheet music

it doesn't........it goes everywhere your blood goes.

When you have a headache, and take aspirin, how does the medicine know where to go?state theatre opera theater

When you take medicine it is introduced into your blood system. Once it gets to the area that is inflamed (which causes the pain/aching) the medicine reacts with the white blood cells which are fighting off the inflammation.
it doesn't "go" to your headache. It generally inhibits the production of inflammatory products that produce pain.
It is automatically digested, just like food. It binds to receptors in your intestines and then goes into your bloodstream. Once in your blood, it gets carried to your receptors in your brain and binds to them. Then, no more headache. The aspirin doesn't "know" where to go, it just gets digested and the chemical does what it is meant to do.