MedlinePlus Herbs and Supplements: All
check it out. it has a ridiculous amount of info on a ton of herbal meds, even creatine. found it at popsci.com.
heres their article on it
Perhaps you’re the type of health nut who takes four or five different vitamin concoctions each morning to support weight loss, anti-aging, good digestion, clear skin and high energy. Or maybe you’re just curious about the medicinal effects of black tea, cranberry juice and licorice. Well, you’re in for a treat. The NIH has put together a very good database of the results of numerous studies about natural remedies, detailing the demonstrated effects on the human body, recommended doses and contraindications.
Many Americans believe that just because a capsule or tincture comes from a health food store and is filled with plant-derived ingredients, it’s safe. But “natural” doesn’t equal “good for you.” (Consider the effects of belladonna, which can be used to treat eye diseases—or as a lethal poison). Plants can contain potent chemicals that might interact with your prescription medications in unexpected ways.
Feeling blue and considering taking St. John’s wort? Do a little research before popping a pill. Turns out the “happy herb” can interact badly with SSRI antidepressants, birth control, antibiotics, chemotherapy drugs… and even Imodium.