ABSTRACT
Kampo medicines containing Bupleuri Radix (Sho-saiko-to and Sho-saiko-to plus Fossilia ossis mastodi and Ostreae testa) were decocted with four kinds of mineral waters and tap water, and the extracts were analyzed for saikosaponin contents by HPLC. The results indicated that the yield of the extracted materials was the largest when Kampo medicines were decocted with the hard water compared with other mineral water extracts. However, the same extract contained the smallest amount of saikosaponin b<sub>2</sub> of those tested. Extractions made with the mineral waters having a weakly acidic or weakly alkaline nature gave similar yields of the extracted materials and saikosaponin b<sub>2</sub> contents.<br>Present results suggest a possibility that decoction using a hard water significantly affects extraction of certain ingredients in Kampo medicine.