Back to nature: A look at raw herbal medicines

Thursday, June 29, 2006
The passion flower is an example of an herb some consumers buy fresh to use medicinally. (Sarah L. Voisin * Washington Post)

With an estimated 19 percent of Americans using herbal medicines and other dietary supplements, jars of capsules and tablets crowd grocery and drugstore shelves. But in some areas, particularly in ethnic communities, many people buy their medicinal herbs in raw plant form.

People with roots in China, Latin America, Africa, the Caribbean and the Indian subcontinent often use herbs in this form because of cultural tradition, because they're less expensive than processed supplements or because some herbs are not available as extracts. Experts say many people also make the mistake of thinking "natural" products are safe, although medicinal herbs can be toxic and are subject to only loose government regulation.

While herbal medicines in any form pose risks, those purchased raw may pose some additional dangers, according to physician Steven Bratman, chief author of a comprehensive herb database, The Natural Pharmacist (TNP) Natural Medicine Encyclopedia.

Because raw plants are not subjected to the kind of chemical analysis that manufacturers generally perform when processing extracts, Bratman said, potency may vary.

Some herbal mixes, such as those used in Chinese medicine, he said, contain plants in the Aristolochia family, which can be toxic to the kidneys.

Indian herbal medicines, he said, may contain heavy metals -- such as lead, mercury and arsenic -- that also can be toxic. Some toxic plants may also be mistaken for harmless ones, particularly given that some plants go by several names.

While the Food and Drug Administration governs sales of medicinal herbs in plant form just as it does bottled supplements, current laws treat them more like foods than drugs and don't guarantee that products are safe, effective, pure or meet any specified standards.

Herbalist Yiping Hu, who has clinics in Bethesda, Md., and Washington, said the suppliers of her herbs wash and boil them in licorice or wine to remove toxins.

But William Obermeyer, vice president for research of, which evaluates dietary supplements and other products, warns that inadequate processing of herbs could allow toxins to remain. Similarly, he said, fungus, mold or toxins could be present in plants that were not washed or dried properly before packing and shipping.

Misidentification of herbs can also pose a danger. Obermeyer cited a 1997 case in which a woman was hospitalized with an irregular heart rate after taking what she thought was an herbal laxative. An investigation found that, instead of containing plantain, the product contained digitalis, an herb capable of causing cardiac arrest.

The supplier later said he had misidentified the herb in its raw form.

One way to avoid misidentification, said Obermeyer, is to find reputable herbal vendors.

"It is about trusting the person who is putting the herbs into the bag," he said.

Herbal medicines can also interact dangerously with prescription drugs. Experts urge patients to consult their doctors before trying any herbal products.

Buying medicinal herbs fresh

Instead of buying bottles of processed supplements, some consumers, including many members of ethnic communities, buy medicinal herbs as plants -- selecting fresh or dried leaves, bark and berries to make teas or to mix into cooking for their purported health benefits.

Herbs can pose risks in any form, and their efficacy is often not proven. Here is a snapshot of what's known about some plants sold as medicines.

Holy basil

* Ethnic group: Indian

* Claim: Reduces inflammation, lowers blood sugar levels in diabetics, stabilizes cortisol levels. Treats heart disease, headache, flu.

* Preparation: Leaves are chopped and boiled with water to make a tea.

* Safety: Could reduce action of anticoagulant drugs. May increase drowsiness from barbiturates.


* Ethnic group: Indian

* Claim: Reduces inflammation, lowers blood pressure, improves sexual stamina in men, boosts immune function, reduces effects of aging.

* Preparation: Powdered form of plant is used to make tea.

* Safety: May cause drowsiness. May magnify effect of sedatives and thyroid hormone pills.


* Ethnic group: Hispanics and Sephardic Jews

* Claim: Relieves digestive upset, heart palpitation and breathing problems. Regulates menstrual cycle.

* Preparation: Used to make tea or in salads.

* Safety: Considered unsafe as a medicine. Can cause stomach irritation, mood changes, sleep problems, skin disorders, increased sun sensitivity and kidney and liver problems.


* Ethnic group: Chinese

* Claim: Helps lower blood pressure and blood sugar, relieves fever and dizziness. Treats impotence, cancer.

* Preparation: Dried berries and root bark can be made into tea or mixed with other herbs to make soups.

* Safety: Can cause nausea and vomiting. Avoid if pregnant or have low blood pressure. May increase side effects of certain medicines.

Source: Tom Wolfe, Lixing Lao, Consumer Reports Medical Guide Natural Medicine Ratings Section, University of Maryland Medical Center, MedlinePlus, The Natural Pharmacist (TNP) Natural Medicine Encyclopedia

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