Pleurisy weed is better known in parts of the country as butterfly weed. The plant is a variety of milkweed native to eastern North America.

Medicinally, pleurisy supports the lungs, providing an expectorating effect, and reducing inflammation and muscle spasms.* Pleurisy weed does have a darker side, however. The alkaloids it contains include some that can be toxic in the mature plant. It is considered toxic to livestock, and not recommended for use by pregnant or breastfeeding women, or for children.