An investigation of herbal supplements by the New York State attorney general’s office carries a sobering message for the rest of the nation as well.

The investigation looked at the store brands of well-known herbal products sold by four prominent national retailers: GNC, Target, Walgreens and Walmart. Among the popular products examined were ginkgo biloba, St. John’s wort and ginseng pills. Four out of five of the products tested did not include any of the herbs listed on their labels. Even worse, hidden ingredients and contaminants could be dangerous to people with allergies to those substances.

That such well-known brands should be found to be fraudulent suggests that the problem infects the entire industry.