Vernonia is a genus of about 350 species of forbs and shrubs in the family Asteraceae. Some species are known as ironweed. Some species are edible and of economic value. They are known for having intense purple flowers. The genus is named for the English botanist William Vernon. There have been numerous distinct subgenera and subsections named in this genus, and some botanists have divided the genus into several distinct genera. For instance, the Flora of North America recognizes only about twenty species in Vernonia sensu stricto, seventeen of which are in North America north of Mexico, with the others being found in South America.
Vernonia amygdalina is commonly used in traditional medicine. Leaf decoctions are used to treat fever, malaria, diarrhoea, dysentery, hepatitis and cough, as a laxative and as a fertility inducer. They are also used as a medicine for scabies, headache and stomach-ache.