Abstract:Through a critical study of herbalogy, it is concluded that the mature seeds of Alpinia zenmubet were used as Caodoukou in ancient times, The original plant of Yutao recorded in Zhiwu Mingshi Tukao may he the species of Alpinia katsumadai. Baidukou used in ancient times may he the seeds of Alpinia katsumadai found in the south of China, or Amomum compactum and Am. kravanh imported from foreign countries.