Proscillaridin in commercial tablet preparations was analyzed by HPLC on a phenylpropyl chemically bonded stationary phase, prepared by treating porous silica with phenylpropyldimethylchlorosilane (PHP). From the elemental analysis data for carbon, the number of bonded PHP surface groups per 1 nm2 of silica (mean pore diameter 13.1 nm, specific surface area 330 m2/g, mean particle size 5.5 microns) in PHP gel was calculated to be 2.07. Using methanol-distilled water (80:20, v/v) as an eluent, the separation of proscillaridin was successfully performed on the PHP column.