herbal medicine

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The study or use of medicinal herbs to prevent and treat diseases and ailments or to promote health and healing.
• noun A drug or preparation made from a plant or plants and used for any of such purposes.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun herbalism
• noun A herbal drug or similar preparation

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a medicine made from plants and used to prevent or treat disease or promote health
• noun the use of medicinal herbs to prevent or treat disease or promote health