Contains strong cardioactive glycosides - CAUTION! Native Americans have used weak root tea to treat heart ailments and rheumatism, and induce sweating and vomiting. The fibrous bark is used to make fishnets, cordage, twine, etc., hence the common name. A friend of ours made paper out of this plant, and found that it produced a dark red dye in the process. The milky sap has been used to treat warts. Laxative. While fairly toxic, this plant has exhibited anti-tumor activity. This plant is a hyperaccumulator of lead and other heavy metals - it has been used to clean up contaminated soils.