and a lot is dangerous.
There is a huge push by Big Pharma for "science based medicine".
This just means treatments that they hold patents on, or have done a study that supports their interests.
like epinepherine for heart attacks. kills you later.
http://roguemedic.com/2012/09/wide-variability-in-drug-use-in-out-of-hospital-cardiac-arrest-a-report-from-the-resuscitation-outcomes-consortium-part-ii/
and even neck immobilization after accidents
http://roguemedic.com/2012/09/confessions-of-a-recovering-cervical-spine-field-clearance-addict-part-i/
This also goes for health food supplements and whole food vitamins.
There is more than a few studies that have changed the apothecarists guesses, and most of it hasn't worked its way down to users yet, because of sales.
only study on echinacea, showed it didn't work, but the dangerous heavy metal zinc did, AFTER you have a cold.