The rootstock is thick, round and fleshy, slightly curved at ends, and contains an orange-red juice, and is about 1 to 4 inches long, with orange-red rootlets. When dried it breaks with a short sharp fracture, little smell, taste bitter acrid and persistent, powdered root causes sneezing and irritation of the nose. The root is collected in the autumn, after leaves die down; it must be stored in a dry place or it quickly deteriorates.
In toxic doses, it causes burning in the stomach, intense thirst, vomiting, faintness vertigo, intense prostration with dimness of eyesight.
The root has long been used by the American Indians as a dye for their bodies and clothes and has been used successfully by American and French dyers.