Several species of Vernonia, including V. calvoana, V. amygdalina, and V. colorata, are eaten as leaf vegetables. Common names for these species include bitterleaf, ewuro, ndole and onugbu. They are common in most West African and Central African countries. They are one of the most widely consumed leaf vegetables of Cameroon, where they are a key ingredient of ndole stew. The leaves have a sweet and bitter taste. They are sold fresh or dried, and are a typical ingredient in egusi soup.
V. amygdalina is well known as a medicinal plant with several uses attributed to it, including for diabetes, fever reduction, and recently a non-pharmaceutical solution to persistent fever, headache, and joint pain associated with AIDS (an infusion of the plant is taken as needed). These leaves are exported from several African countries and can be purchased inexpensively in grocery stores aiming to serve African clients for about $1.50/225gm pkg. frozen. The roots of V. amygdalina have been used for gingivitis and toothache due to its proven antimicrobial activity.
Vernonia species are used as food plants by the larvae of some Lepidoptera species including Coleophora vernoniaeella (which feeds exclusively on the genus) and Schinia regia (which feeds exclusively on V. texana).The above information taken from the Wikipedia link: http://en.wikipedia.org/wiki/Vernonia