The poisonous plant Gelsemium sempervirens, described in Agatha Christie's novel The Big Four, contains the highly toxic alkaloid gelsemine, which is commonly known as "yellow jasmine" and as Carolina jasmine in Japan. The highly poisonous G. elegans plant, which is closely related to G. sempervirens, grows wild in southern China and Southeast Asia. The dried roots of this plant have been preserved as the medicinal product "Yakatsu" at Shosoin in Nara City since ancient times.