In the book "Prevention Magazine Complete Book of Natural & Medicinal Cures," Eclectic Institute is listed as one of eight recommended firms which are also well-known suppliers to natuopathic physicians and clinics. They also mention Nature's Way and Nature's Herbs, two very common brands at health food stores. From everything I've read, the difference between tinctures, powders, and dried herbs mostly comes down to convenience and personal preference. Keep in mind that Wormwood
is essentially a mild poison, the best word to describe it, with only short term use (no more than a couple weeks) recommended. Long term use can harm the central nervous system.