The aim of this study was to clarify whether sennosides were contained in dietary supplements containing senna stem and in the raw materials of senna stem for dietary supplements. The identification and determination of sennosides were performed with thin layer chromatography and high performance liquid chromatography. Moreover, plant contents of herbal teas were classified into leaf, stem and others, and these were identified by comparison with characteristic components of senna using a stereoscopic microscope. The amount of sennosides ranged from about 0.2 mg to 11 mg in a dose of dietary supplements. In three of these 11 samples, senna leaves and midribs were contained. However, in eight of the samples, the plant fragments were not recognized. In five raw materials of senna stem, the amounts of sennosides were from 9.5 mg/g to 14.6 mg/g. These raw materials of senna stem consisted not only of senna stem, but also senna leaves and midribs. We believe that sennosides of dietary supplements are derived from senna leaves and midribs, which contaminate the raw materials of senna stem.
