A potential class action alleging so-called herbal supplements sold by GNC stores aren’t really herbal at all was filed in Miami federal court.

The lawsuit filed Monday is the first of its kind in the Southeast since the New York state attorney general’s office notified the Pittsburgh-based company Feb. 2 that it must stop selling products that may be adulterated or mislabeled. Cease-and-desist letters demanding more information about ingredient-verification procedures went to four retailers, also including Target Corp., Walgreen Co. and Wal-Mart Stores Inc.