clipped from: www.fun-on.com 
Herbs are not regulated by the FDA for safety or efficacy. So search the label for a seal of approval from the USP (United States Pharmacopeia) or CL (Consumer-Lab.com), which indicates it has been approved by certified academic laboratories.
It's best to tell him if you're considering supplements. Some herbs can interact with certain meds, including those for high blood pressure, diabetes, and depression, as well as blood thinners and even OTC drugs.
More isn't necessarily better and could be dangerous. Always follow dosing instructions.