In 2735 B.C., a Chinese emperor recommended an extract from the ma huang plant (known as ephedra in the Western world) as a treatment for respiratory illness. Today, the chemical ephedrine is extracted from the plant and used as a decongestant (e.g., pseudoephedrine). Codeine, derived from opium, has long been used as an analgesic and cough suppressant.

During the Golden Age of Western herbology, which occurred from 500 B.C. to 200 A.D., Western physicians and scholars classified hundreds of plants useful in healing. By the Middle Ages, every household had an herb garden to supply it with medicines. Rhubarb was used as a laxative. Salicin, a forerunner of aspirin (acetylsalicylic acid), was derived from the bark of the willow tree. The tranquilizer laudanum, derived from the poppy, was later used to treat the "vapors" experienced by Victorian ladies.

By World War II, herbology was losing popularity in the West. Penicillin and other "wonder drugs" seemed to be cure-alls. And the war itself had cut off supplies of herbs from around the world. The advent of the drug industry with its synthetic medicines seemed to ring a death knoll for herbology, yet plants remain a major source of drugs today. For example, the previously mentioned ephedrine, digitalis (a heart strengthener), and vincristine (an antitumor drug) are all plant-derived.

Ironically, the same research that threatened to make herbal medicine extinct has also proven its efficacy, breathing new life into it. We now know that the peppermint used for digestive disorders since 1800 B.C. relieves nausea and vomiting by mildly anesthetizing the stomach lining. Laboratory analysis has shown that herbs contain vital vitamins, minerals, and natural chemicals that may be essential to curing a diseased body. Echinacea, for instance, is derived from the purple coneflower and was used by herbalists for centuries to fight infection. Research has shown that echinacea stimulates the production of white blood cells, thereby boosting the immune system.

Many moderns, in support of herbal therapies, believe that extracting the chemical rather than using the whole plant eliminates such active ingredients as minerals, volatile oils, bioflavonoids, and other substances that support a particular herb's medicinal properties. Some feel that isolated or synthesized compounds may have harmful side effects because they are so concentrated.

Generally speaking, herbs are used to cleanse the blood, warm and stimulate the body, increase surface circulation, increase elimination of wastes, reduce inflammation, and calm and soothe irritation. Herbs may be used internally as pills, syrups, and infusions, or externally as poultices, plasters, and liniments. An external application of clove oil, for instance, will stop the pain of toothache, as will tincture of hops. Herbs are commonly used as additives to bath water-either full body baths or baths for the foot, eye, or face. Moist herbal wraps, either hot or cold, can be used on specific affected parts of the body. These wraps are especially effective for sore, tense muscles such as those in the neck, shoulders, back, or jaw when temporomandibular joint syndrome (TMJ) is present.