[Survey of botanical origin of tongcao (medulla Tetrapanacis) and identification of its commercial products]

Through the investigation on botanical origin, output and sales of Togcao in producing areas, it has been proved that there are twenty-two species of six families used as Tongcao. The medicinal parts are the pith of stems or petioles. The provinces featuring more species and larger output of Tongcao are Sichuan, Yunnan, Guizhou, Guangxi, Hunan and Shaanxi. A hundred and two pieces of commercial samples collected from twenty-six provinces in China, Hongkong area, Japan, Malaysia, Thailand, Singapore and Republic of Korea have been identified. The result shows that both Xiaotongcao and Datongcao are called by the same name Tongcao. The main species is Xiaotongcao, which takes a proportion of 70% in Tongcao. And the Tongcao(Tetrapanax papyriferus, taking a proportion of 20%) as recorded in the Chinese Pharmacopoeia (1995 edition) is seldom used.