Like the milkweed family, all parts of the plant contain a white, milky sap. Buds on hemp dogbane root system. Hemp dogbane is listed as a poisonous plant in many references. The milky sap does contain a cardiac glycoside similar to that found in digitalis species. Little is known concerning the toxicity of dogbane to livestock.
Animals find the plant distasteful.
Reported cases of poisoning are rare. Small greenish-white flowers are produced in clusters at the ends of branches from June through August. These pods contain reddish-brown seeds that have a tuft of white fluffy fiber at one end. The seed is easily carried by wind. New plants readily become established from seed in areas free of other plant competition.