Prescription medications aren’t given to patients
without a list of potential side effects and
ingredients, along with proof that it worked and
was safe before it was approved. Even then, we run
in to problems with medications being pulled from
the market years later.
Polls show that 68% of Americans have it
wrong about the safety of vitamins and
supplements. The truth is herbal manufacturers are
not required to report side effects, manufacturers of
vitamins and minerals can make claims about
safety and effectiveness without evidence and the
FDA does not approve herbal products before
sale. There has always been a problem about dosing and constitution. The only change occurred in 2007 so now the
FDA can make sure a product contains what the
label says it contains. When they started doing this,
at least half of those inspected had problems.
Source
url. http://forum.facmedicine.com/threads/10-things-that-will-shock-you-about-vitamins-and-supplements.16708/

But please, I want to add that vitamins are good, but could be harmful if consumed excessively, especially the fat-soluble ones...

Too long to read