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 luteolus, commonly known as Golden Poison-rope in English and Ubuhlungubendlovu in isiZulu, is a South African indigenous deciduous climbing shrub with stems that can be 2 – 6 meters long found in the KwaZulu-Natal and Limpopo provinces. Plants grow in low coastal forest on sand dunes, 30-100 m, and densely wooded slopes in the Soutpansberg, 1400-1600 m. It has slightly hairy leaves and creamy flowers with pinkish markings and long tendrils, which are produced in spring.