Abstract: Yanhusuo, the dried tubers of a species affiliated to Corydalis remota Fisch. ex Maxim., is one of the most famous Chinese herbal drugs frequently used as an analgesic in this country. The taxonomical treatment of Yanhusuo has been very confused and difficult because of the wide variations of its morphological features. However, the isoquinoline alkaloids in the above plants were found to be qualitatively and quantitatively different. The aporphinc type alkaloids such as glaucine were found in Yanhusuo while corynoline type alkaloids found in C. remota. These results can be used to differentiate them each other, even by a simple authenticated TLC chromatogram described in this paper. Therefore, it is more rational to consider that Yanhusuo as an indepen-dent species Corydalis yanhusuo W. T. Wang ex Z. Y. Su et C. Y. Wu than as C.turtschaninovii Bess f. yanhusuo Y. H. Chou et C. C. Hsu or others.

Key words: Corydalis