Strophanthus is a genus of 35-40 species of flowering plants in the family Apocynaceae, native mainly to tropical Africa, extending to South Africa, with a few species in Asia, from southern India to the Philippines and southern China. The name (strophos anthos, “twisted cord flower”) derives from the long twisted threadlike segments of the corolla, which in one species (S. preussii) attain a length of 30-35 cm. The genus includes vines, shrubs and small trees. The leaves are opposite or whorled, simple broad lanceolate, 2-20 cm long, with an entire margin. Several of the African tribes used Strophanthus as the principal ingredient in arrow poison. Plants from this genus produce toxic alkaloids and cardiac glycosides g-strophanthin (syn. ouabain), k-strophanthin and e-strophanthin. As ordinarily administered, the drug acts on the heart before influencing any other organ or tissue. Often indeed no other action can be observed. It is used to produce the drug Ouabain which was taken as a cardiac stimulant to treat heart failure, and is similar to the drug Digoxin produced from Digitalis purpurea.

Strophanthus gratus, commonly known as Climbing Oleander, is a climbing shrub native to tropical Africa. This plant is renowned for its beautiful, fragrant, and showy flowers, which are typically white or pink with a star-like shape. Strophanthus gratus is most famous for its seeds, which contain toxic compounds called cardiac glycosides, particularly ouabain. These compounds have a history of use in traditional medicine for their potent effects on the heart, though they are also highly toxic if misused. The plant has been utilized in various African cultures for both medicinal purposes and in hunting, as the seeds can be used as a poison on arrows. Despite its toxic nature, Strophanthus gratus remains an important species for its medicinal potential and role in traditional practices.