A genus of woody climbers of the dogbane family (Apocynaceae), natives of tropical Asia and Africa. They are the source of arrow poisons. The dried, greenish, ripe seeds (see illus.) of Strophanthus hispidus and S. kombe contain the glucoside strophanthin, which is much used in treating heart ailments. Strophanthin acts directly on heart muscle, increasing muscular force. It causes the heart to beat more regularly and decreases the pulse rate. Strophanthin is a precursor of cortisone, which is used in the treatment of arthritis.