The Dangers of Not Knowing What's in a Supplement

The danger isn't just in not knowing what's in a supplement. Make sure companies list side effects and drug interactions on the label. St. John's Wart is an obvious one but there are so many, so many products on the market that you can't even know necessarily what's in them. Some might want to ask themselves if a substance is so powerful and so miraculous then why is it being sold as a dietary supplement?