Eupatorium (pei lan)

What is eupatorium? What is it used for?

Eupatorium is the name for a large genus of plants - approximately 600 altogether - that grow in areas ranging from South America and Mexico to China, Japan and Korea. Most forms of eupatorium are perennial herbs, but a few are annuals. Many are shrublike or treelike in appearance.

In the United States, the most common species of eupatorium is boneset, which is described at length elsewhere in Herb Central.

The typical eupatorium plant resembles a bush and bears large, showy clusters of flowers that range in color from white to blue to purple to pink. While the plant can grow in shaded or sunny areas, it requires moist soil to thrive. The aerial plants, such as the flowers, leaves and stems, are used in herbal remedies. Typically, they are harvested in the summer and fall, then cut into slices and dried in the sun before use.

In traditional Chinese medicine, eupatorium is considered to have pungent and neutral properties, and is associated with the Spleen, Lung and Stomach meridians. Its main functions are to resolve dampness and relieve heat.

Eupatorium can be taken internally for digestive disorders such as diarrhea, heartburn, flatulence and indigestion. Externally, the aerial parts can be soaked in oil and applied to the scalp to treat dandruff. In addition, eupatorium root may improve circulation.

How much eupatorium should I take?

The typical dosage of eupatorium is 5-10 grams, taken as part of a decoction or powder. Some practitioners recommend that larger doses of eupatorium be taken if the herb is fresh.

What forms of eupatorium are available?

Eupatorium is most commonly available as part of a decoction. Some herbal shops and Asian markets sell fresh and or dried eupatorium, either raw or in pill and powder forms.

What can happen if I take too much eupatorium? Are there any interactions I should be aware of? What precautions should I take?

Eupatorium contains the essential oil thymol. Research has shown that large doses of thymol can cause stomach irritation, along with headaches, vertigo, and problems with the circulatory and respiratory systems. As such, it must be taken with extreme caution. As of this writing, there are no known drug interactions with eupatorium. As always, however, make sure to consult with a licensed health care provider before taking eupatorium or any other herbal remedy or dietary supplement.

References

• Bown D. Encyclopedia of Herbs and Their Uses. London: Dorling Kindersley, 1995.
• Duke JA, Ayensu ES. Medicinal Plants of China. Reference Publications, Inc., 1985.
• James L, et al. Plant toxicants in milk. In: Colegate S, Dorling P (eds.) Plant Associated Toxins. Wallingford: CAB International, 1994.
• Warden JC, Castle J. A checklist of the flora of Roan Mountain State Park, Carter County, Tennessee. Report to the Upper Cumberland Studies Program. Tennessee Technological University, Cookeville TN, 1993.
• Woerdenbag HJ, Bos R, Hendriks H. Eupatorium perfoliatum L – the boneset. Z Phytother 1992;13:134–9.