The authorities, New York State attorney general, said they had conducted tests on top-selling store brands of herbal supplements at four national retailers — GNC, Target, Walgreens and Walmart — and found that four out of five of the products did not contain any of the herbs on their labels. Ginseng pills at Walgreens, promoted for “physical endurance and vitality,” that contained only powdered garlic and rice Walmart, the authorities found that its ginkgo biloba, a Chinese plant promoted as a memory enhancer, contained little more than powdered radish, houseplants and wheat. Three out of six herbal products at Target — ginkgo biloba, St. John’s wort and valerian root, a sleep aid — tested negative for the herbs on their labels. From GNC, Herbal Plus brand: Gingko Biloba: No gingko biloba found Did detect allium (garlic), rice, spruce and asparagus St. John’s Wort No St. John’s Wort found Did detect allium (garlic), rice and dracaena (a tropical house...