Herbal Medicine is the therapeutic use of plants, and is the most ancient form of health care known to humankind. An herb is a plant or plant part valued for its medicinal, savory or aromatic qualities. Herb plants produce and contain a variety of chemical substances that act upon the body. Herbs have been used to treat virtually every disease and condition. The use of herbs ranges from pain relievers, hormone balancers, energizers, sleep aids, stomach soothers, skin soothers, and treatment of everything from allergies to cancer, from depression to hysteria. Herbs are used for both prevention and treatment.