Abstract:Objective: To provide new evidences for the identification of Herpetospermum pedunculosum seeds and other substitutes. Method: Microscopic examination of the cross sections and powers of the seeds of H. pedunculosum, Momordica charantia, Thladiantha setispina and M. cohinchinensis were made to characterize the drug materials. Result and conlusion: The external and internal structure of T. setispina and M. charantia were studied for the first time. Two types of different branched starry sclereids was found in M. cohinchinensis. Comparative studies on external and internal structure were carried out on seeds of the 4 species. As a result, they could be distinguished by external characteristics such as shape, size and color of their seeds, and by internal structure such as size and type of sclereid, epidermis and sub-epidermis cell of seed coat.