Herbal medicine ("herbology" or "herbalism") is use of plants for medicinal purposes, and the study of such use.

Herbal medicine is an ancient form of health care.
Plants have been the basis for medical treatments through much of human history, and such traditional medicine is still widely practiced today. Modern medicine recognizes herbalism as a form of alternative medicine, as the practice of herbalism is not strictly based on evidence gathered using the scientific method. Modern medicine, does, however, make use of many plant-derived compounds as the basis for evidence-tested pharmaceutical drugs, and phytotherapy works to apply modern standards of effectiveness testing to herbs and medicines that are derived from natural sources.
The scope of herbal medicine is sometimes extended to include fungal and bee products, as well as minerals, shells, and certain animal parts.

Western herbalism classifies many herbs according to their opposing activity: for example, herbs may have anti-inflammatory, antimicrobial, antispasmodic, or hypotensive effects.
Additional terms describe a supportive action: for example, adaptogenic herbs (those that increase resilience and resistance); tonics (supportive of vital energy); and emmenagogues (supporting the female reproductive system).
Herbal preparations may be prescribed for ingestion as teas, as capsules or tablets, or as extracts or tinctures.
Herbs may also be prepared as essential oils to be used topically, as are herbal preparations made into salves, balms, or ointments.

Adapted from Wikipedia, the free encyclopedia. Internet. Accessed on January 18, 2016.