California

with supplements and similar OTC preparations you often have no idea what you're taking and in what quantities. A cup of tea made from actual mulberry leaves may contain a minimal amount of the active ingredient and do no harm; a capsule containing concentrated extract likely contains a much higher dosage, but there's no law requiring the supplements provider to say how much (as far as I know)

I few years ago I had major surgery. As part of the prep, I had a sheet from the anesthesiologist listing foods and drugs to avoid for about two weeks prior to the surgery. It included quite a few of the herbs and spices I cook with: when I talked with her nurse-practitioner, he explained that what they wanted people to avoid was taking capsules of garlic and ginger - the two I remember - since they were so much more concentrated that the raw cloves or roots and that there was often no way to know just how much of the active ingredients they contained (which were fine in normal culinary amounts)