In case you didn't already read this news back in early February, tests conducted by the state of New York found that very few herbal supplements they tested contained any at all of what they claimed to contain.
This brief video from pediatrician Aaron Carroll quickly summarizes what they found:
If you want an even quicker overview, here it is:
On February 3 of this year, the New York State Attorney General's office reported (link) that tests of herbal supplements sold by major retailers showed that only 21 percent had any at all of the herbal ingredient advertised on the label.
I repeat: If you bought one of those supplements, then on average four out of five times were getting absolutely none of what you thought you were buying. Instead you were getting ground up house plants or asparagus or heaven knows what. In fact, as Dr Carroll notes, at least one supplement contained wheat but was explicitly labeled "gluten free." (Gluten is of course a protein found in wheat and related grains.)
Moreover, these weren't supplements sold via spam emails or out of the back of a car; the ones tested were bought from GNC, Target, Walgreens, and Walmart, and they are almost certainly sold by other retailers as well. Of the supplements bought at Walmart, only 4 percent contained any detectable trace of the herbal ingredients listed on the label.
Speaking of supplements, see also Dr Carroll's recent report about new studies on vitamin D.