Relationship between adenosine content and different growth period and different tissue of Chinese crude drug Di Huang ( root tuber of Rehmannia glutinosa ) was investigated by the method of HP LC .It showed that adenosine content is apparently higher at harvest time ( October) , but no distinguished difference of adenosine co ntent in cortex and xylem .A denosine is rich in maternal root which should not be abandoned when the crude drug is utilized.