There has long been debate about the benefits of modern versus traditional medicine, but there is growing acceptance in Western countries of the virtues of traditional medicine, including medicinal plants that are widely used in many parts of the world. An exhibit at the U.S. Botanic Garden in Washington showcases medicinal plants from around the world.
Herbal remedies have been used to treat illness and disease for thousands of years. In many cases, modern science has verified the healing powers of these plants. According to the World Health Organization, 25 percent of modern medicines are made from plants initially used in traditional medicine.
Medicinal plants and herbal preparations are widely used in China, Africa and many other parts of the world. In Europe and the United States, however, they have more often been considered a supplement to modern medicine, but even in these regions there is growing interest in the healing properties of plants.
Nathan Bartholomew is in charge of the medicinal plants exhibit at the U.S. Botanic Garden. He says many people, particularly in the United States, are not aware of the curative properties some plants provide.
"Medicinal plant knowledge is one of the most ancient fields on the planet," he said. "Pretty much every plant species around, [even] common weeds we see in the sidewalk, are medicinal plants."
More than 100 species of herbs and plants are on display at the U.S. Botanic Garden exhibit. The plants are grouped by regions of the world and labeled according to their countries of origin.
Mr. Bartholomew says there are over 20,000 species of medicinal plants in the world and half of them are endangered. He says many other species of plants have yet to be researched for their medicinal properties.
The Botanic Garden official says that one plant or tree can have thousands of different medicinal uses. Native Americans, for example, used five main medicinal plants, each of them having thousands of different uses for different ailments.
He says the exhibit aims to educate the public about the latest science regarding medicinal plants, and about how vulnerable some plants are.
"We're striving to provide the most up-to-date plants and the most clinical research that is going on with medicinal plants, as well as a lot of the plants that are threatened and endangered, and are very important for conservation efforts," he added.
Among the plants in the collection is one known as the sausage tree, because of its sausage-shaped fruit. The fruit is widely used throughout Africa for treating medical problems, such as epilepsy and respiratory ailments. And a plant known as the Chinese star tree is now being used in some countries to treat the bird flu virus. The garden also features southernwood, a herb which provides the active ingredient in the malaria medicine artemisinin.
Xiaoiui Zhang is coordinator of traditional medicine at the World Health Organization (WHO).
"According to the international research, we found two plants now make a great contribution to the health. For example, artemisinin, that is an anti-malaria drug," she noted. "It is effective for all of the [parasites], it doesn't matter if it is for the Asian one or the African one. And another one is tameflu, WHO recommends to use that for the anti-bird flu."
But Ms. Zhang says the World Health Organization (WHO) does not promote medicinal plants as being better than Western medicine, but does urge people to be careful in the use of either one.
"Each system, either traditional or Western medicine, they have their own advantages and disadvantages," she added. "So at WHO, our policy is to encourage integrating traditional medicine into the national health system where it's appropriate."
The Botanic Garden exhibit has attracted a variety of people. Washington resident Michelle Brunson says she came partly because she wants to be a botanical illustrator, an artist who draws plants.
"I'm studying to become a botanical illustrator, so I have an interest just in the plants themselves visually, but I also have an interest because, in my studies, I have learned how many of the species are being killed in deforestation, and the ones that need to be conserved are the ones I'm really interested in," she said.
Ms. Brunson also says she works for the Marijuana Policy Project in Washington, which advocates making the marijuana plant medically available to seriously ill people who have the approval of their doctors. Advocates say the drug, which is illegal in the United States, helps reduce pain. The plant is not among the collection at the U.S. Botanic Garden.