The raw material of lanatoside C was examined for preparation of the "Lanatoside C Reference Standard". The analytical data obtained were: melting point, 247.4 degree C; optical rotation, [alpha]20(D) = + 34.0 degree, loss on drying, 6.93%; infrared spectrum, the same as that of the Lanatoside C Reference Standard (Control 784); thin-layer chromatography, two impurities detected; high-performance liquid chromatography, several impurities detected and the total amount estimated to be about 1.26%; assay by spectrophotometry, 103.0%. Based on the above results, the candidate material was authorized as the Lanatoside C Reference Standard (Control 981) of the National Institute of Health Sciences.