1. Family and genus classification: Hedyotis diffusa or Houttuynia cordata, a perennial herb of Houttuynia of Saururaceae, and Radix Isatidis, also known as Ginseng and Salvia miltiorrhiza, belongs to Stachys of Labiatae.

2. Geographical distribution: Crocodile roots are widely distributed in Shaanxi, Gansu and the provinces south of the Yangtze River basin in China, and also in other Asian countries such as Japan and Java, while the origin of Yintiaocai is mainly concentrated in yanshi city, Luoyang City, Henan Province.