Herbal extractions are formulations that separate the soluble active medicinal and flavor components out of the inert, fibrous material of the herb. These may be used in cooking, for example, vanilla extract, and in health care as herbal teas or tinctures. The various techniques that have been developed over the centuries extract active constituents from the herb, to make them available to the body.
The traditional herb tea is water extract, either an infusion or a decoction, that easily extracts the water soluble constituents in the plant. However, a combination of water and alcohol has the advantage of dissolving both water soluble and insoluble constituents, and is usually the form used by medical herbalists. Depending on technical details, such extracts may be called tinctures, fluid extracts, or liquid extracts.
Alcohol/water based extracts have a number of advantages. Because they are concentrated, a smaller amount of extract is needed; the alcohol acts as a preservative, so these extracts have a long shelf life; and the method of preparation allows for more accurate dosing.
Dry extracts have been developed to make the constituents appropriate for use in tablets, capsules, and other medicinal forms.