Boneset is a perennial flowering herb native to the Eastern United States and Canada. It grows in meadows and marshland ranging from Nova Scotia to Florida, and as far west as Texas and North Dakota. The plant's scientific name is Eupatorium perfoliatum, and it gets its common name from its traditional use in medicine.
Eupatorium perfoliatum has long, dark green leaves, and tiny white flowers. It often grows near Phalaris arundinacea, or reed canary grass. Eupatorium perfoliatum is gathered when in bloom, during the summer months.
Boneset is so called because it was historically used by European settlers in the United States to cure dengue fever, also known as breakbone fever. Though dengue fever does not actually affect the bones, it causes severe pain in the muscles and joints. The common name of Eupatorium perfoliatum may also be related to its historical use in splints. Because the leaves of the plant grow wrapped around the stem, a belief arose that using Eupatorium perfoliatum leaves in the bandages of a splint could help heal broken bones.
European settlers in the United States learned about Eupatorium perfoliatum from the Native Americans, who used the plant to break fevers by inducing sweating. Because of this property, the plant is also called agueweed, feverwort, or sweating-plant. In the 19th century, Eupatorium perfoliatum was used in the United States as a remedy for many different ailments, including cold, flu, indigestion, malaria, and typhoid.
Eupatorium perfoliatum is usually administered as a hot or cold tea. One or two teaspoons of the dried herb are steeped for 10 to 15 minutes in a cup of boiling water. The infusion is bitter and astringent, and sometimes causes nausea. While chemical studies of boneset have not definitively revealed any therapeutic compounds, they suggest the possible presence of immunostimulants. Eupatorium perfoliatum has no history of adverse side effects outside of vomiting.
Many other Native American plants in the Eupatorium genus include "boneset" in their name because of association with Eupatorium perfoliatum. These include Eupatorium pilosum or rough boneset, Eupatorium resinosum or pine barren boneset, and Eupatorium serotinum or late boneset, and Eupatorium sessilifolium or upland boneset. Eupatorium perfoliatum can form hybrids with other Eupatorium species, such as Eupatorium serotinum.