What’s that in your St. John’s wort supplement, or your ginkgo biloba pill? What if it’s not the plant you thought at all? The New York State Attorney General’s office DNA-tested dozens of bottles of big-brand supplements to determine what they actually contained, the New York Times reports today.

The Attorney General’s office used DNA barcoding to test for DNA from plants in bottles of herbal supplements officials bought at popular pharmacy chains. As a result, the office is forcing GNC, Target, Walgreens, and Walmart to pull products from their shelves. The companies are selling supplements, under their own brands, whose DNA don’t match up with their labels.