Abstract: As previously reported, the drug Huang-Ch'i is mainly the roots of Astragalus membranaceus and A. membranaceus var. mongholicus, family Leguminosae. In a few districes, the roots of A. chrysopterus, A. tongolensis, A. maowenensis and A. floridus are also used. The drug Hung-Ch'i is the roots of Hedysarum polybotrys, used as a substitute for Huang-Ch'i, and is said to be equally effective. Besides, adulterants of Huang-Ch'i derived from 14 species of plant were also reported. In this paper, the authors described the morphology and histology of Huang-Ch'i and Hung-Ch'i. It is found that no marked difference is present which can be served to distinguish the roots of the five species of Astragalus, viz. Astragalus membranaceus A. membranaceus var. mongholicus, A. chrysopterus, A. tongolensis and A. floridus. Hung-Ch'i can be easily distinguished from the genuine Huang-Ch'i by the presence of prisms of calcium oxalate in the parenchymatous cells surrounding the bundles of phloem- and xylem-fibres.