99% of all people take medications without even questioning, what's in it, how does it work, or much less how does the medication know what part of the body to work on?
But if you ask a mechanic if it is a good idea to add leak_stop to a radiator, the first thing the mechanic is going to ask you is how does it know which leak or which hole to plug? And if you've actually tried the products that say they will stop radiator leaks, you know that it doesn't work. That it generally plugs every hole in your radiator and your radiator no longer works at all.
So why would you trust a doctor or pharmacist that says that this pill/medication that you're taking is only going to affect the part of the body that you're having a problem with?
Have you ever seen a medication commercial on TV that has not had a disclaimer or a list of side effects?
And how many commercials have you seen followed by a commercial by a law firm that is filing a lawsuit against a medication that has caused injury or death?
Have you ever really asked the doctor how a medication works? And did they give you an answer?
The next time your at a pharmacists ask them how does ibuprofen work? And how does it know to work only on my headache?