Gentian, from various species of Gentiana, is a bitter root and an excellent digestive remedy. European herbalists are very fond of "bitters" to stimulate and tone the digestive system, and they rate gentian as the best of them all. Several brands of alcoholic extracts of gentian root are available here, most with other plant ingredients added for flavor. For example, Angostura Bitters, a popular ingredient of cocktails which you can buy in most liquor stores and supermarkets, is essentially a tincture of gentian root and has good medicinal properties. For sluggish digestion, poor appetite, or flatulence, try taking a teaspoon of Angostura Bitters before or after meals (experiment to see which works best for you). If you do not like it straight, try diluting it with sparkling water to make a (relatively) nonalcoholic "mocktail." Gentian root is quite harmless and quite effective.