RESUMEN
AIM To determine the quality constant of Chinese medicine and to establish a method of grades evaluation of Cortex Moutan decoction pieces.METHODS Cortex Moutan decoction pieces' morphological indexes should be observed and measured,the contents of phenol and paeoniflorin were measured by HPLC.Cortex Moutan decoction pieces was graded according to the quality constant of Chinese medicine which was calculated.RESULTS Cortex Moutan decoction pieces could be divided into three grades by the quality constant of Chinese medicine,the cutoff point of the firsts was greater than or equal to 1.56;the second was greater than or equal to 1.12 but less than 1.56;while the third was less than 1.12.CONCLUSION This method combines the apparent parameters of Cortex Moutan decoction pieces with its intrinsic quality,which can devide grades of it objectively and provides a reference for its classification.