Encyclopedia of Herbal Medicine

Book Preface

In the twenty years since the first edition of this encyclopedia in 1996, herbal medicine has gone through unprecedented change. Herbs, which have always been the principal form of medicine in developing countries, have again become popular in the developed world, as people strive to stay healthy in the face of chronic stress and pollution, and to treat illness with medicines that work in concert with the body’s defenses. A quiet revolution has been taking place. Tens of millions of people now take herbs such as ginkgo (Ginkgo biloba, p. 100) to help maintain mental and physical health, and increasingly people consult trained herbal professionals and naturopaths for chronic or routine health problems. Increasingly too, scientific evidence is accumulating to show that herbal medicines can provide treatment that is as effective as conventional medicines but with few side effects. Sales of herbal medicines continue to grow year after year—by over 50 percent in the U.S. since 2000—and several mainstream pharmaceutical companies now manufacture and market herbal medicines.

Plant Medicines

The variety and sheer number of plants with therapeutic properties are quite astonishing. Some 50,000 to 70,000 plant species, from lichens to towering trees, have been used at one time or another for medicinal purposes. Today, Western herbal medicine still makes use of hundreds of native European plants, as well as many hundreds of species from other continents. In Ayurveda (traditional Indian medicine) about 2,000 plant species are considered to have medicinal value, while the Chinese Pharmacopoeia lists over 5,700 traditional medicines, mostly of plant origin.

About 500 herbs are still employed within conventional medicine, although whole plants are rarely used. In general, the herbs provide the starting material for the isolation or synthesis of conventional drugs. Digoxin, for example, which is used for heart failure, was isolated from common foxglove (Digitalis purpurea, p. 202), and the contraceptive pill was synthesized from constituents found in wild yam (Dioscorea villosa, p. 91).

Ecological Factors

The increased use of medicinal herbs has important environmental implications. Growing herbs as an organic crop offers new opportunities for farmers, and sometimes, especially in developing countries, opportunities for whole communities. In northeastern Brazil, for example, community-run herb gardens grow medicinal herbs that are sold to local hospitals. Doctors at the hospital then prescribe these medicines for their patients. The rise in popularity of herbal medicines, however, also directly threatens the survival of some wild species. Demand for goldenseal (Hydrastis canadensis, p. 105) has become so great that it now fetches around $140 a pound (£170 a kilo). It was a common plant in the woodlands of northern America two centuries ago, but is now an endangered species, with its survival in the wild threatened by overcollection. This example is by no means unique, and, sadly, many species are similarly threatened across the planet. The extinction of plant species as a result of over-intensive collecting is nothing new. The herb silphion, a member of the carrot family, was used extensively as a contraceptive by the women of ancient Rome.

Silphion proved difficult to cultivate and was gathered from the wild in such large quantities that it became extinct during the 3rd century ce. Today, if herbal medicine continues to grow at its present rate, it is imperative that manufacturers, suppliers, practitioners, and the public use only produce that has been cultivated or wildcrafted in an ecologically sensitive manner.

About This Book

In the past, books on herbal medicine have tended to focus either on the traditional and folkloric use of plants or on their active constituents and pharmacology. The , which features over 550 plants, aims to cover both aspects. It discusses each plant’s history, traditions, and folklore, and explains in simple terms what is known from scientific research about its active constituents, actions, and potential new uses.

It is easy when concentrating on the scientific aspect of herbal medicine to forget that much, in some cases all, that we currently know about a particular plant results from its traditional use. Moreover, even when a plant has been well researched, herbal medicines are so complex and variable that what is currently known is rarely definitive, but rather a sound pointer as to how it works. Sometimes the traditional use, insofar as it is based on the experience of practitioners, provides an insight into how best to use an herb that is missing from scientific knowledge alone. Herbal medicine is, after all, both a science and an art.

In choosing the plants profiled in the Encyclopedia, the aim has been to select herbs that are commonly used in different parts of the world and are considered to have particular health benefits. The index of key medicinal plants (pp. 54–155) contains many herbs that are readily available in health stores and pharmacies, for example St. John’s wort (Hypericum perforatum, p. 106). It also includes herbs that are more commonly known as foods, such as lemon (Citrus limon, p. 82), but which, nonetheless, are valuable medicines. The index of other medicinal plants (pp. 156–283) contains some less commonly known but important medicinal herbs, such as andrographis (Andrographis paniculata, p. 167), a traditional Indian medicinal plant that stimulates recovery from infection and supports normal liver function.

A global overview of the history of herbal medicine puts the development of different herbal traditions from earliest origins to the present day into perspective. This is complemented with features on herbal medicine in Europe, India, China, Africa, Australia, and the Americas, providing a rounded picture of herbal medicine worldwide. Herbal medicine is nothing if not practical in its approach, and the Encyclopedia has a detailed self-help section with advice on preparing and using herbal medicines totreat a range of common health problems.

If more people come to appreciate the immense richness of the world of herbal medicine and are able to benefit from the curative properties of medicinal herbs, this book will have achieved its aim.