They've been used for a thousand years, but guess what? Scientific method wasn't around for thousands of years, was it?
We can't be sure about stuff that was invented in the last century for how much has science gone ahead. For example, Aspirin is an over the counter drug and is used almost daily by thousands of people. But we now know how harmful it is and how much side effects it can cause. If it was invented today it would never have been put on a shelf to begin with even as a prescription drug, let alone OTC.
So if we learned so much more about aspirin in less than a 100 years, how in the world do you believe that stuff people used for 1000s of years is harmless, OR that safety data acquired by them is reliable?
@moon777light 10 years of science research is NOTHING in pharmacology, I'm sure you're aware if that