Objective:The research aimed to analyse the medicinal serum of Prepared Radix Rehmanniae and explore the material base of Nourishing Yin effects on Prepared RadixRehmanniae.Method:Based on Yin-Deficiency Rats model

established HPLC fingerprints of Prepared Radix Rehmannia

The constituents absorbed into blood were determined by comparing HPLC fingerprints of Prepared Radix Rehmanniae

medicinal serum of Yin deficiency rats and blank serum.Result:After oral administration

one Chromatographic Peak was found in the medicinal serum as the same location as Prepared Radix Rehmanniae.Conclusion:The Chromatographic Peak in the medicinal serum which is as the same location as Prepared Radix Rehmanniae is the original constituent of Prepared Radix Rehmanniae absorbed into blood.and might be active component of nourishing yin.Further studies of them is helpful to clarify the bioactive material Base of Prepared Radix Rehmanniae.